By far the biggest was in Moscow, on Sakharov Avenue, a broad boulevard named after the Soviet dissident, Andrei Sakharov.

Ilya, a 31-year-old arts worker, came to the rally with a black-and-white photo of Sakharov pinned to his parka. He said that many of Sakharov’s democracy slogans from the Soviet perestroika period are relevant to Russia today.

In a reminder that Russia, the world’s biggest country, can make large and sudden political changes, this Sunday, Christmas Day, marks 20 years since former Soviet leader Mikhail Gorbachev appeared on national television and dissolved the Soviet Union.