Kola Superdeep Borehole

69°23′N, 30°36′E

Kola Peninsula, near Zapolyarny, Murmansk Oblast, Russia — deepest artificial hole on Earth

[from the public record]

69.3833, 30.6000 · view on OpenStreetMap →

What's documented

The Kola Superdeep Borehole was the deepest artificial hole ever drilled — 12,262 meters in cratonic granite of the Kola Peninsula. Soviet drilling ran from 1970 to 1992. At depth, the rock reached ~180 °C and behaved plastically; the hole would not stay open. The project was abandoned and the site shut down. The wellhead was welded over in 2008; the surface complex has been allowed to deteriorate.

Notable & intriguing

At 12,262 m, the Kola Superdeep Borehole remains the deepest hole ever drilled into the Earth — deeper than the Mariana Trench is below sea level, though only a small fraction of the way through the continental crust.

Kozlovsky (ed.), The Superdeep Well of the Kola Peninsula, Springer, 1987.
Soviet geologists reported finding microscopic plankton fossils 2 billion years old at ~6.7 km depth, and free water in cracks at depths where the existing models had said the rock should be impermeable.

Kola Drilling Project final report, 1992; Smithsonian Magazine retrospective, 2015.
The “Well to Hell” hoax. In 1989 a Finnish newspaper and (later) the American newsletter Praise the Lord reported that Soviet engineers at Kola had lowered a microphone to ~14 km and recorded the screams of the damned. The audio was lifted from the 1972 Italian horror film Baron Blood. The hoax remains one of the most-cited UFO-adjacent stories about the borehole.

Folklore; investigated by Rich Buhler / Snopes (1989, 2003).
The wellhead was sealed with a welded steel cap in 2008 and the surface complex was abandoned. The site is reachable by road but unmaintained; photographs since 2010 show the buildings half-collapsed on the tundra.

Atlas Obscura entry, 2014.

Public-record items already documented about this subject. Folklore is labelled. Sources cited where the specificity warrants it.

Public-record imagery

The borehole site as of 2020 — the surface complex left to half-collapse. Wikipedia Commons · CC BY-SA 4.0 · Шелковников Евгений Анатольевич · 2020

The wellhead, welded shut in 2008 and never reopened. Wikipedia Commons · CC BY-SA 3.0 · Rakot13 · 2012

The Soviet-era complex on the tundra outside Zapolyarny. Wikipedia Commons · CC BY-SA 3.0 · Andre Belozeroff · 2007

Abandoned 'Slyudyanka' base of the Central Kola Geological Expedition — the regional Soviet-era infrastructure for the deep-drilling program. Like the borehole itself, post-Soviet austerity left the whole geological complex to dissolve back into the tundra. Wikimedia Commons · CC BY-SA 4.0 · Vsatinet · 2013

Referenced in the codex

1. We Are the Substrate The claim, the substrate-logic argument in three points, the Apkallu emerging from the deep waters to teach civilization. The long study, said plainly.
3. The Observers Above The third layer. The rectangle under the Vostok ice. The same rectangle in two other oceans. The man at Starbucks's "nearby galaxies" claim, taken seriously without being believed.