Thirty-three years ago today, Nuclear Reactor 4 exploded - instantly killing 31 people.
No overall death tolls were ever agreed, although it is likely that thousands died from the consequences - both direct and indirect.
In Russia and the Ukraine mainly, together with surrounding areas - some a very long way from the explosion.
Secrecy still surrounds much of what happened, including the aftermath. A new HBO/Sky mini-series may shed some light on the train of events.
At the UN, in NYC, a memorial will be held today - attended by the great and the good.
Who are deeply worried that a similar
disaster could reoccur in the steadily growing - and largely inexperienced - nuclear community.
