The 10 Deepest Man-Made Holes Ever Dug Into the Earth
Humans have been digging, drilling, and blasting into the ground for as long as we’ve needed water, diamonds, gold, or oil. Some of these holes were carved out with picks and shovels, others with drill bits spinning miles beneath the ocean floor. Either way, the results are almost impossible to picture: shafts so deep the rock itself gets hot enough to require industrial cooling, and boreholes so long they’d stretch past the cruising altitude of a jumbo jet if you turned them sideways.
This countdown pulls together the most extreme excavations on record, mixing scientific research holes, mining shafts, and record-setting oil and gas wells. We ranked them by approximate depth, using the most widely cited figures from geological and industry sources, since exact numbers are sometimes disputed or measured differently depending on whether you’re talking vertical depth or total drilled length.
#10. The Big Hole, Kimberley, South Africa
Before machines took over, thousands of miners with picks, shovels, and buckets carved this enormous pit into the ground during the diamond rush of the 1870s and 1880s. It’s considered one of the largest excavations ever dug entirely by hand, and it produced tons of diamonds before mining shifted underground. The open pit reaches roughly 215 meters deep, though its true scale is best appreciated from the sheer width of the crater it left behind.
An interesting fact: at its peak, estimates suggest tens of thousands of miners worked the site with hand tools, turning a quiet hill into a gaping crater in just a couple of decades.
#9. The Woodingdean Well, England
Dug entirely by hand between 1858 and 1862 by workhouse laborers, this well near Brighton was created simply to find water for a rural parish. Workers descended into total darkness with candles and basic tools, chipping through chalk bedrock for years. It’s widely recognized as the deepest hand-dug well in the world, reaching close to 392 meters below the surface.
An interesting fact: the well took four years to complete using only manual tools and hand-hauled buckets, a testament to the sheer physical endurance demanded by Victorian-era engineering.
#8. TauTona Mine, South Africa
Once billed as the deepest mine on Earth, TauTona’s gold-bearing shafts descend nearly 3,900 meters below the surface near Carletonville. Miners ride a series of elevators for the better part of an hour just to reach the working face, where rock temperatures climb high enough to require intense cooling systems. The mine has operated since the early 1960s, tunneling further down as accessible gold near the surface ran out.
An interesting fact: the round trip commute for workers, from surface to rock face and back, can take longer than some people’s entire daily work shift above ground.
#7. Mponeng Gold Mine, South Africa
Mponeng has taken over as the world’s deepest operating mine, with tunnels extending roughly 4 kilometers underground. Temperatures at that depth can climb high enough to be dangerous without intervention, forcing engineers to pump in ice slurry just to keep the air breathable for miners. It remains an active gold mine, still being extended deeper as reserves are chased further into the crust.
An interesting fact: scientists have found bacteria living in the rock near the mine’s deepest tunnels, isolated from sunlight for millions of years and surviving on chemical energy alone.
#6. Bertha Rogers Well, Oklahoma, USA
Drilled in 1974 in search of natural gas, this well plunged to around 9,583 meters, making it one of the deepest onshore wells drilled in the United States at the time. Instead of gas, crews famously hit molten sulfur, which brought the ambitious project to an abrupt halt. It still stands as a landmark in American drilling history, even though it never became commercially productive.
An interesting fact: for a brief period after its completion, Bertha Rogers held bragging rights as one of the deepest holes drilled anywhere on land.
#5. Tiber Field Well, Gulf of Mexico
Drilled from the Deepwater Horizon rig before its infamous 2010 accident, this well in the Gulf of Mexico reached a measured depth of over 10,000 meters, combining water depth with the rock drilled beneath the seabed. It remains one of the most extreme offshore drilling achievements, tapping oil reserves buried far beneath ultra-deep water. The technical challenge of drilling that far down, through miles of ocean and rock, pushed offshore engineering to its limits.
An interesting fact: the rig that drilled this record-setting well was the same one later involved in the catastrophic spill that followed.
#4. Al Shaheen Field Well, Qatar
This offshore well in Qatar’s Al Shaheen oil field used extended-reach drilling to travel more than 12,000 meters in total length, though much of that distance runs horizontally rather than straight down. Engineers steered the drill bit sideways for miles to reach oil deposits that couldn’t be tapped with a simple vertical shaft, letting a single rig access oil spread across a huge underground area.
An interesting fact: extended-reach wells like this one can travel farther sideways than they do downward, essentially threading a needle through rock for kilometers.
#3. Kola Superdeep Borehole, Russia
Started in 1970 as a pure scientific experiment, this narrow borehole in northwestern Russia reached a true vertical depth of about 12,262 meters, making it the deepest hole ever drilled straight down. Soviet scientists hoped to study the crust directly, but rock at that depth turned out to be hotter and more plastic than expected, forcing the project to stop. The hole is barely wider than a dinner plate despite its staggering depth.
An interesting fact: the borehole is now sealed with a welded metal cap, and the abandoned research site has become something of an eerie tourist curiosity.
#2. Odoptu OP-11 Well, Sakhalin Island
Part of the Sakhalin-I project off the Russian coast, this well used extended-reach drilling to stretch beyond 12,300 meters in total length. Oil companies developed this technique specifically to reach undersea reserves without building new platforms further out at sea, letting one rig cover an enormous underground footprint. The well briefly held the title of longest oil well ever drilled.
An interesting fact: the well was drilled at such a shallow angle that the bit traveled nearly horizontal for most of the journey, curving gently rather than plunging straight down.
#1. Chayvo Field Wells, Sakhalin Island
Also part of the Sakhalin-I development, wells drilled here have repeatedly broken records for total drilled length, with some reportedly exceeding 13,000 meters, making them the longest oil wells ever created. Engineers use extended-reach drilling to snake the well bore far out under the seabed, reaching oil reserves that would otherwise require an entirely separate offshore platform. The scale of these wells represents one of the most ambitious feats of drilling engineering on the planet.
An interesting fact: despite reaching further than any other man-made hole, these wells only descend a modest distance vertically, since most of their incredible length runs almost sideways beneath the ocean floor.
Whether carved by hand over painstaking years or drilled by machines pushing past the limits of engineering, these holes remind us how far people will go, quite literally, to find water, gold, or oil. Depth records keep shifting as new drilling techniques emerge, so don’t be surprised if a well somewhere quietly breaks one of these marks in the years ahead.
