Human stupidity
Chernobyl, Russia
Chernobyl
the nuclear meltdown at Chernobyl.
Chernobyl, Ukraine, in 1986
One of the four reactors at Chernobyl
there was a meltdown at a nuclear plant that caused irrevoable damage and nuclear posioning for generations to come. It is still considered dangerous to go there.
Meltdown in Chernobyl - 2004 TV was released on: USA: 2004
Meltdown in Chernobyl - 2004 - TV was released on: USA: 2004
The worst nuclear accident occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in the Ukraine (under the management of authorities in Moscow).
Nowhere as far as I can find. Perhaps you are thinking of the 1986 Chernobyl steam explosion and graphite fire. This was in the USSR and although the graphite fire melted much of the core, it was not a meltdown in the usual sense associated with nuclear reactors.
Makarov
There was no famous disaster (or anything else) at Chernobyl in Russia as there is no such place. However for the disaster that occurred in Chernobyl in the Ukraine, please see the related question.