The Chernobyl 4 reactor was destroyed by a nuclear explosion, not a steam one, according to research published in the journal Nuclear Technology.

The reactor, 130 kilometres of Kiev, Ukraine, exploded in on April 25, 1986, killing 30 people, and inducing acute radiation poisoning in 134. Today, encased in thick concrete, it stands at the centre of a 2600 square-kilometre exclusion zone.