Twenty-Seventh CPSU Congress opens

Gorbachev’s first major policy initiative emphasized faster economic and technological development. The campaign began before perestroika became a broad reform program and retained top-down...

The USSR began a unilateral moratorium on nuclear explosions, timed to the anniversary of the Hiroshima bombing and initially set through January 1, 1986. The pledge made Kazakhstan’s test-site...

The leaders met for the first time at the Geneva Summit. Their talks began a new phase of direct engagement, but the encounter remained a negotiation between nuclear superpowers whose decisions...

Reagan and Gorbachev issued a joint statement affirming that nuclear war could not be won and must never be fought, while agreeing to continue talks. The declaration mattered as a diplomatic signal...

The Soviet leader proposed eliminating nuclear weapons worldwide by 2000. The plan was a diplomatic initiative by a nuclear superpower and an appeal to reduce the danger its own arsenal helped create.

A reactor accident released radioactive materials across Ukraine, Belarus, Russia, and beyond. The evacuation and cleanup exposed residents and workers to serious risk, while secrecy delayed public...

After radiation alarms in Sweden and reports abroad, Soviet news briefly acknowledged an accident. The delay and lack of detail eroded trust among communities facing exposure and demonstrated the...

In his televised address, Gorbachev discussed the accident after nearly three weeks of limited public disclosure. His speech did not erase the consequences of delayed evacuation and uneven access to...

After years of confinement in Gorky, physicist and dissident Andrei Sakharov was allowed to return to Moscow. His release signaled a change in political climate while leaving many political...

Gorbachev called for democratization within the party and greater competition in elections. The proposals widened public debate but kept reform under party leadership and did not yet establish...