A Deadly Shape Emerges
On April 26, 1986, a reactor at the Chernobyl Nuclear Power Plant exploded, creating one of the most devastating nuclear disasters in history.
In the months that followed, a peculiar and deadly structure formed beneath Reactor No. 4. Dubbed “The Elephant’s Foot” for its wrinkled, organic appearance, this mass of molten nuclear material, concrete, and metal became notorious for emitting lethal levels of radiation.
It was discovered in December 1986, and to this day, remains one of the most dangerous artifacts left by the disaster.
A Mass That Burned Through Concrete
The Elephant’s Foot was created when uranium fuel, graphite moderator, steel, sand, and concrete fused into a lava-like flow called corium.
This radioactive material burned through over two meters of reinforced concrete, snaked through pipes and fissures, and settled in a corridor about 15 meters southeast of the destroyed reactor. It came to rest in Room 217/2, approximately six meters above ground level. Though the photographed mass is the most famous, it is only one portion of several corium accumulations in the facility.
Radiation So Intense It Killed in Minutes
By the time it was found, the Elephant’s Foot was emitting around 8,000 to 10,000 roentgens per hour—about 80 to 100 grays. That level of exposure could kill a person within minutes. Its composition included silicon dioxide, uranium, iron, zirconium, calcium, and other elements.
The uranium content, roughly 10% by mass, contributed both alpha and gamma radiation. The gamma rays posed a serious external hazard, while the alpha particles raised concerns about inhalation risks as the mass began to deteriorate.
From Solid Mass to Crumbling Hazard
Attempts to study the Elephant’s Foot faced major obstacles. The extreme radiation levels made human proximity almost impossible. Remote-controlled equipment struggled to collect samples, and even armor-piercing bullets were fired into the mass to obtain usable fragments.
Over the years, as radioactive decay reduced emissions, researchers gained closer access. In 1996, Artur Korneyev, deputy director of the New Safe Confinement Project, entered the chamber to photograph the Foot using a camera triggered by a flashlight.
By 1998, the mass had begun to crack and disintegrate into radioactive dust. By 2021, the once-impervious formation had softened into a sandy texture, but it still contained dangerous materials.
The structure continues to emit gamma radiation, primarily from caesium-137 and other long-lived fission products. While it no longer kills within minutes, it remains a key focus of containment and monitoring efforts at the Chernobyl Exclusion Zone.
In the wreckage beneath Chernobyl’s Reactor No. 4 lies a deadly creation.
Discovered in December 1986, the “Elephant’s Foot” is a lava-like mass of molten core and building materials that once gave off enough radiation to kill a person in under three minutes…🧵👇 pic.twitter.com/DiGHP0urqU
— Detective Tiger's Stories (@TigerDetective) June 14, 2025