Underground

We live on a thin skin. Beneath it are voids that water spent millions of years dissolving, shafts people sank looking for salt and gold and coal, cities carved out of soft rock by populations hiding from armies, and a biosphere of microbes that may outweigh everything walking around up here. Below all of that is a planet we have never seen and never will, the deepest hole ever drilled reached twelve kilometres and stopped, which is not quite a third of the way through the crust, let alone the six thousand to the centre. Everything we know about the inside of the Earth we learned by listening to earthquakes. The underground is also where the record is kept: it buried Pompeii and preserved it, held Tutankhamun for three thousand years, and kept the oldest art anyone has found on walls that no daylight ever reached. This archive goes down through all of it, the caves, the mines, the digs, the tunnels, the life, the descent, the deep earth, and the underworld people imagined long before they could measure any of it.

A chronological documentary of 647 moments spanning 4000 BC–50 BC on Loreline.

Curated by Olivier · last updated 2026-08-22

Eras

  1. - The cult of Mithras and London's lost temple. The London Mithraeum and the underground initiatory cult that met in windowless rooms across the Roman empire.
  2. - Geothermal Energy Is Changing. Real Engineering on Quaise Energy's millimetre-wave drilling, an attempt to reach supercritical geothermal resource depths that conventional bits cannot.
  3. - Harriet Tubman: Visions of Freedom. PBS on the woman who returned repeatedly into slave territory along the Underground Railroad.
  4. - The Graveyard at the Center of the Earth. PBS Eons on the slabs of subducted ocean floor that sink to the core-mantle boundary and pile up there.
  5. - Sanxingdui: the discovery that rewrote Chinese history. An evidence-led account of the bronze masks, gold sceptres and jade from the Sichuan sacrificial pits.
  6. - Inside the new excavations at Pompeii. NBC reports from the once-in-a-generation dig underway in the buried Roman city.
  7. - Replicating Lascaux. The facsimile programme built to let visitors see the paintings while the original stays sealed against microbial damage.
  8. - The geology of Carlsbad Caverns. How the Permian reef of the Guadalupe Mountains became the Carlsbad cave system, and how speleothems form inside it.
  9. - Inside Son Doong: a cave with a forest, a river and clouds. Filmed expedition through Son Doong in Vietnam, which is large enough to hold its own jungle, watercourse and internal weather.
  10. - Jay Famiglietti on GRACE and the Global Water Crisis. The former NASA JPL water scientist on how gravity satellites revealed the scale of groundwater depletion.
  11. - Mammoth Cave: a way to wonder. Hour-long PBS documentary on Mammoth Cave National Park, the world's longest known cave system, from prehistoric Native American use onward.
  12. - Chiremba Balancing Rocks - Harare3514. Prehistoric rock paintings depicting human and animal figures on a sandstone surface at Chiremba Balancing Rocks.
  13. - The Big Business of Drilling Deep Into the Earth. Bloomberg on next-generation geothermal, where fracking technology is being repurposed to open sites previously off-limits.
  14. - The salt mines of Wieliczka. A tour of the Wieliczka workings in the Carpathian foothills, with their salt lakes, caverns, chapels and carved figures.
  15. - New discoveries in the Christian catacombs of Rome. A research update on the history, imagery and epigraphy of the Roman catacombs.
  16. - The forest was full of cities we couldn't see. How airborne LiDAR changed archaeology, and where its results have been over-read.
  17. - The Underground Network That Helps Forests Survive. NOVA on the mycelial networks beneath forests and how fungi move nutrients between trees.
  18. - Caving expedition, Palawan 2025. Field footage from a 2025 caving expedition on Palawan in the Philippines.
  19. - Intraterrestrials: Hunting Life Beneath the Surface. Microbiologist Karen Lloyd introduces her firsthand account of searching for the microbes that live inside the Earth's crust.
  20. - Earthworm Ecology with Nick Henshue. A soil ecologist on what earthworms actually do to soil structure, and why the answer differs between a garden and a forest.
  21. - Altamira and the controversy that rewrote history. How the Cantabrian cave's paintings were dismissed as forgery for decades before being accepted as Palaeolithic.
  22. - Darwin's Unexpected Final Obsession. PBS Eons on the earthworm, the subject of Darwin's last book in 1881, and his argument that worms remake the soil of the whole land surface.
  23. - The First Emperor's mega-tomb. Albert Lin uses remote sensing on the unexcavated burial mound of Qin Shi Huang, guarded by the Terracotta Army.
  24. - The rock-hewn churches of Lalibela. The Met on the Ethiopian churches carved downward into volcanic rock rather than built up from it.
  25. - Yellowstone's Magma Chamber: A Hot Mess. The Yellowstone Volcano Observatory's monthly update on what is actually known about the magma system heating the park's hydrothermal features.
  26. - Thai cave rescue. NOVA follows the July 2018 operation in which international cave divers brought twelve boys and their football coach out of the flooded Tham Luang cave.
  27. - Anclote river mound plaque. The information sign marking the location of an indigenous shell midden at the mouth of the Anclote River, in west-central Florida.
  28. - Cascadia: Why the Risk Estimate Keeps Getting Worse. PBS Terra on newer research into the Cascadia megathrust and what it changes about the expected rupture.
  29. - An Earthworm in its Natural Habitat at Kyabobo National Park. An earthworm moving across a damp, rich soil in the forest.
  30. - Underground Connections: How Mycorrhizal Fungi Shape Ecosystems. A University of Sheffield researcher on the nutrient trade between plants and mycorrhizal fungi, and on what that partnership does and does not do.
  31. - The greatest historical discoveries of 2024-2025. An evidence-based round-up of the year's finds and the reanalyses that changed accepted chronology.
  32. - The history of the Mammoth Cave guides. On the enslaved Black cave guides who mapped much of Mammoth Cave's 400 known miles and made it one of America's earliest tourist attractions.
  33. - Inside the world's first nuclear waste tomb. A visit to Onkalo, cut into Finnish bedrock to hold spent fuel permanently.
  34. - The Four Most Ruthless Ants We've Ever Filmed. Deep Look's macro footage of fire ants, kidnapper ants, honeypot ants and Argentine ants, and the underground colonies they run.
  35. - Secrets of Pompeii's Dead. National Geographic examines new excavation evidence from Pompeii and Herculaneum identifying victims of the AD 79 Vesuvius eruption.
  36. - Polymetallic nodules: life-giver or energy future?. Filmmakers were mid-shoot on the seabed nodules when researchers announced in July 2024 that the rocks appeared to be producing oxygen in the abyss.
  37. - What Is the Impact of Lithium Mining?. BBC News on lithium extraction from brine beneath Chile's Atacama and the water cost of pulling it up.
  38. - Five discoveries from Pompeii's new excavations. A tour of finds from the ongoing Regio IX, Insula 10 excavation, filmed with access from the Pompeii Archaeological Park.
  39. - The science behind giant sinkholes. BBC World Service on why the ground collapses without warning, and how karst dissolution sets the stage decades in advance.
  40. - The oldest temple in the world. Palaeoanthropologist Ella Al-Shamahi visits Gobekli Tepe for the BBC.
  41. - Calthemite formation on a wall at Most Holy Trinity Cemetery, Brooklyn, New York, US
  42. - Budapest's Millennium Underground. Continental Europe's oldest metro line, opened in 1896, still running in its shallow cut-and-cover box.
  43. - A Swedish Arctic town moves its church for the mine. Reuters on the two-day relocation of Kiruna's 113-year-old church to make way for expansion of the world's biggest underground iron ore mine.
  44. - Kiruna church is moved before the mine swallows it. AP films the Kiruna Church and its belfry being hauled five kilometres east to the new town centre in August 2025.
  45. - The lost tunnels of the Wieliczka salt mine. Beneath Wieliczka in southern Poland run more than 180 miles of workings, including chapels and a cathedral carved entirely from rock salt.
  46. - The trillion-dollar race to mine the ocean floor. Four Corners on the companies moving to harvest metal-rich nodules from the Pacific abyss and the scientists warning of irreversible damage.
  47. - How ancient salt mining transformed prehistoric Europe. The brine springs of the Carpathians and the rock salt of Hallstatt, and how control of salt reshaped Bronze Age economies.
  48. - The history of Mithraism. The spread of the Mithraic mysteries through the Roman army and its rivalry with early Christianity.
  49. - Inside Mount Hood's hidden glacier caves. In 2011 two Oregon cavers found more than a mile of tunnels inside the Sandy Glacier, the largest known glacier cave system in the lower 48 states, and began mapping it.
  50. - An introduction to caving gear. What cavers actually carry and why, from helmets and lights to rope kit, in an environment that is dark, wet, cold and unforgiving.
  51. - The many lives of the Soviet dissident movement. Benjamin Nathans on how a clandestine movement operated within, and against, the Soviet legal system.
  52. - Life in darkness: how life survives without sunlight. Documentary on sulphurous, lightless cave ecosystems including Movile Cave in Romania, sealed off for millions of years.
  53. - Cave divers explore the cenotes of the Yucatan. Thirty years of diving has shown that the Yucatan cenotes are not isolated wells but openings into one connected network of flooded passages.
  54. - Excavating Gobekli Tepe: interview with Jens Notroff. Archaeologist Jens Notroff, who worked years at the site, on what the excavation actually found.
  55. - A British cave rescue medical officer on the work. Brendan Sloan describes the volunteer structure of British cave rescue teams and treating casualties underground.
  56. - Critical Minerals and Rare Earth Elements. Geologist Terry Panhorst on where critical minerals form in the crust and why their supply chains matter.
  57. - Sutton Hoo and its global connections. Curator Sue Brunning shows how objects in the 1939 ship burial link early medieval England to Europe and Asia.
  58. - Congo produces its first traceable artisanal cobalt. The state cobalt agency delivers 1,000 tonnes of traceable artisanal cobalt, a first step toward formalising a sector that supplies much of the world's battery metal.
  59. - Europe's most famous bog bodies. Tollund Man and Grauballe Man, preserved over 2,000 years in Danish peat and thought to be sacrificial victims.
  60. - Into Earth: learning to cave dive. A Danish underwater photographer works through full cave diver training in Playa del Carmen, and the hazards the course exists to address.
  61. - The royal salt mines of Poland. Polish public broadcaster episode on the medieval royal salt mines at Wieliczka and Bochnia, a UNESCO World Heritage site.
  62. - Inside the mystery of Earth's giant crystals. Documentary tracing giant gypsum crystals from Roman mines to Europe's largest geode at Almeria and the Naica cave in Mexico.
  63. - Landsat Takes Yellowstone's Temperature. USGS on using satellite thermal remote sensing to track more than 10,000 thermal features fed from below.
  64. - The Hidden World of Plant Roots. Stanford biologist Jose Dinneny on roots as active explorers of the soil rather than passive anchors.
  65. - Inside South Africa's deadly Stilfontein mine disaster. A 2024 government crackdown on illegal mining at Stilfontein left hundreds of men trapped underground for months without food or water.
  66. - Geothermal Energy's Massive Leap Forward. The Economist's energy editor on whether new geothermal drilling could scale past nuclear power.
  67. - The 262 New Species Named in 2025. Natural History Museum scientists on the year's newly described species, including worms, fungi and invertebrates from soil and cave habitats.
  68. - Prairie Dogs as Ecosystem Engineers. The Smithsonian on black-tailed prairie dogs as a keystone species whose burrowing creates habitat for dozens of other grassland animals.
  69. - Top Five Yellowstone Geologic Stories of 2025. The observatory's year in review, covering hydrothermal activity, monitoring results and the rumours it had to correct.
  70. - Guerrero Coyote de Tula en el MNA. Vista de la pieza del Guerrero Coyote de Tula del Museo Nacional de Antropología que algunos expertos relacionan con Ce Acatl Topiltzin, Quetzalcoatl.
  71. - Hand stencils in Sulawesi may be the oldest cave art. Euronews on claims that stencil paintings in an Indonesian cave date to about 67,800 years ago.
  72. - Fig. 6.2. Ritual enclosure of Lalibela adjucent to one of the Lalibela rock hewn churches

…527 further moments continue the chronology here. Full text archive: /loreline-text/underground.md

  1. - The machine that changed our understanding of history. How a 1900 sponge-diving find off Antikythera produced a geared astronomical calculator two millennia old.
  2. - An Underground Railroad hiding place found in a New York museum. Historians identify a concealed space in a Merchant's House Museum closet wall.
  3. - HS2's 450,000 finds in a secret warehouse. The BBC is shown the vast store of objects unearthed by the archaeologists working ahead of the HS2 line.
  4. - Are Cascadia and the San Andreas Linked?. Chris Goldfinger presents evidence for partial synchronisation between ruptures of the northern San Andreas fault and the Cascadia megathrust.
  5. - Stone Age Temple Mystery. NOVA on Gobekli Tepe, where hunter-gatherer monuments predate agriculture and overturn assumptions about how civilisation began.
  6. - The 1979 hostage-taking in Carlsbad Caverns. In 1979 armed men held more than 100 visitors in the Big Room, 750 feet below the surface, in one of the strangest incidents in US national park history.
  7. - The Wood Wide Web, Thirty Years Later. Christian Schwartz revisits the wood wide web three decades on, weighing what the evidence actually supports against how the idea has been popularised.
  8. - Yamadera, Part II - Yamadera7486. Rock-cut memorial tablets and grave markers carved into the cliff face at Yamadera (Risshaku-ji) temple complex. Modern photograph of an ancient site.
  9. - Building Resilience in Alberta's Bats Against White-Nose Syndrome. A 2026 science seminar on white-nose syndrome, which reached Alberta in 2024 after killing millions of North American bats.
  10. - How Soviet citizens escaped censorship. The samizdat circuit: carbon copies, typewriters and hand-to-hand distribution under the censor.
  11. - A Hidden Magma Plumbing System on Mars. The Geological Society of America covers a new study finding buried magmatic plumbing on Mars, a comparison point for reading Earth's own.
  12. - A rare journey inside Son Doong. 60 Minutes takes Scott Pelley into the largest known cave passage in the world, deep in the Vietnamese jungle.
  13. - South Africa opens its first new underground gold mine in fifteen years. West Wits Mining opens a shaft in Johannesburg, betting that high gold prices make old deposits viable again while illegal mining continues.
  14. - "Сейсмограф" Seismometer in Moscow Institute of Physics and Technology 20260330 133932. Seismometer in Moscow Institute of Physics and Technology This photo was created by Lesless. It is not in the public domain, and use of this file outside of the licensing terms is a copyright violati.
  15. - The history of the Paris Catacombs. How the 18th-century clearance of the Cemetery of the Innocents filled the disused limestone quarries with six million dead.
  16. - The Cascadia Megaquake Is Inevitable. PBS Terra on the Cascadia Subduction Zone, the offshore fault running hundreds of miles along the Pacific Northwest and overdue for a magnitude 9 rupture.
  17. - 1.9-Billion-Year-Old Bedrock Will Hold Spent Nuclear Fuel. AP descends the Onkalo shaft as the world's first permanent spent-fuel disposal facility prepares to begin operations in Finland.
  18. - Belowground Biodiversity in Northeast India. A SPUN Underground Explorer samples soil fungi across rainforest, alpine meadow and cold desert to see how much diversity is hidden below.
  19. - Suzanne Simard Said Trees Talk. The Evidence Is Complicated.. Traces Simard's 1997 Nature paper on carbon transfer between trees, the 'wood wide web' framing the editors gave it, and the scientific pushback that followed.
  20. - AI used to reconstruct a Pompeii victim's face. Reuters on the first use of AI facial reconstruction on a victim of the AD 79 eruption.
  21. - Why Drilling to the Mantle Is Almost Impossible. Business Insider on why the Kola borehole barely scratched the crust, and on the technologies being proposed to go deeper.
  22. - Uplistsikhe - Uplistsikhe8141. Cave dwellings and rock-cut chambers of the ancient troglodyte city of Uplistsikhe, with a medieval Christian basilica visible on the upper right. Modern photograph of an ancient site.
  23. - Uplistsikhe - Uplistsikhe8144. A basilica-style brick church at the Uplistsikhe cave town complex, situated on a rocky promontory above a river valley. Modern photograph of an ancient site.
  24. - The 2025 Big Horn Mountains caving expedition. Presentation to the Meramec Valley Grotto on an August 2025 expedition to the caves of the Big Horn Mountains in Wyoming.
  25. - Life in Pompeii. David Suzuki's documentary on the science being used to read the city's oldest and deepest layers.
  26. - The price of iron ore: relocating a Swedish city. DW follows the relocation of Kiruna in northern Sweden as the world's largest underground iron ore mine undermines the town.
  27. - Lithium rising: the race for critical minerals. Full-length documentary filmed across five countries on the competition for lithium, cobalt and copper behind electric vehicles and battery storage.
  28. - Should we mine the deep ocean?. BBC World Service asks whether the seabed can supply the metals the energy transition needs, or should be left undisturbed.
  29. - What Are Induced Earthquakes?. A primer from a hydrogeology lab on earthquakes triggered by injecting fluid into the subsurface.
  30. - African Volcanic Plumbing Systems. An IAVCEI commission webinar with researchers presenting current work on the subsurface magma systems beneath African volcanoes.
  31. - Writers underground: Soviet samizdat 1967-1982. How hand-typed publications passed hand to hand became a real threat to the Soviet state.
  32. - Mapping 110 Quadrillion Kilometres of Fungal Threads. SPUN and AMOLF researchers publish in Science the first global estimate of the total length of mycorrhizal mycelium in soil.
  33. - Life Without Sunlight: The Creatures of Movile Cave. A tour of Movile Cave in Romania, sealed from the surface for millions of years, whose animals depend on chemosynthetic bacteria rather than the sun.
  34. - A Seismic View of Mars, From Crust to Core. Ross Maguire on the more than 1,000 marsquakes InSight recorded between 2018 and 2022 and what they reveal about a single-plate planet's interior.
  35. - Hallstatt: a prehistoric salt mine as a data archive. Salt has been won at Hallstatt for over 7,000 years, and the salt has preserved tools, textiles and everyday objects that survive nowhere else.
  36. - Vindolanda 2026 excavation update. Dr Marta Alberti-Dunn reports new features and finds from the current season at the Roman fort on Hadrian's Wall.
  37. - Cairnpapple in West Lothian. A kite aerial photo of Cairnpapple looking northwards.
  38. - The hermit caves of Mount Athos. The cliffside caves where Orthodox monks have lived in complete solitude for centuries.
  39. - A Hydrothermal Explosion Caught on New Monitoring Gear. On 13 June 2026 Yellowstone's newest geophysical monitoring sites recorded a small hydrothermal explosion at Biscuit Basin.
  40. - Drilling Into the Mantle: The Kola Superdeep Hole. Engineering account of the Soviet Kola SG-3 borehole, which reached 12,262 m between 1970 and 1992. Covers the drilling technology and why the rock behaved unexpectedly at depth.
  41. - The Molecule Behind the Naked Mole-Rat's Bee-Like Society. Nature reports research identifying a molecular basis for the eusocial structure of naked mole-rat colonies, where one queen breeds and the rest do not.
  42. - Twenty great discoveries of 2025-2026. A myth-busting survey of the most significant archaeological finds announced across the past two years.
  43. - Top archaeological discoveries of 2026 so far. Lost cities, ancient pandemics and other finds announced in the first half of 2026.
  44. - The archaeological discovery of Petra. Tristan Hughes on the rock-cut city, its tombs and how European travellers reached it.
  45. - 海軍出水航空隊の掩体壕跡. Photograph showing 海軍出水航空隊の掩体壕跡.
  46. - A wartime aircraft revetment shelter, Izumi, Japan. The remains of a semi-underground revetment shelter built to protect aircraft at the former Izumi naval air group base in Kagoshima, Japan.
  47. - Is Yellowstone's North Caldera Rim Rising?. USGS on decades of measured uplift and subsidence on the caldera's north rim, and a new period of uplift that began last year.
  48. - Do Fungi Help Invasive Willows Spread in Patagonia?. Field research on whether soil fungi mediate the replacement of Patagonia's native willows by non-native ones.

Full text archive: /loreline-text/underground.md

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