In June 1991 I ran the White Nights Marathon in St. Petersburg, Russia, USSR. The race began at 11 PM on June 21st in celebration of the Summer Solstice. As a consequence, most of it in the wee hours of the morning, in darkness.
In 1991 the Soviet Union was in an economic and social crisis. Two months later the leader of the USSR, (Gorbachev) was kidnapped in a failed coup attempt. On Jan 1, 1992 the USSR dissolved.