The Sasovo Explosion
In the early hours of a spring night, a huge blast shook a Russian town, shattering windows, and left a crater in a field. No one has found a cause.
What was reported
In the early morning of 12 April 1991, a powerful explosion shook the town of Sasovo, about 350 km south-east of Moscow. Windows broke across the town and people thought a bomb or even a nuclear blast had gone off.
Nearby, investigators found a fresh crater about 30 metres wide and 3 metres deep. Some residents said they had seen glowing balls of light and heard rumbling in the hours before, and that radios crackled with interference just before the blast.
Explanations offered
No explosives, meteorite fragments or industrial cause were found. Many of the early theories have been dropped, and most researchers now suggest a sudden release of gas from deep underground, possibly hydrogen. It remains officially unexplained.
- When
- 12 April 1991
- Where
- Sasovo, Ryazan Oblast, Russia
- Witnesses
- Townspeople across Sasovo
- Status
- Unexplained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.