A gray pall of fog descended over the city Sunday, accompanying a national day of mourning across Russia to remember the 224 victims who died after a Russian airliner crashed in Egypt.
As the evening moved into a murky night, a few hundred people gathered spontaneously on the city's main square, across from the Winter Palace, laying flowers and lighting candles.
The cause of the crash is still unknown; Russia's Interstate Aviation Committee, which is helping Egyptian authorities investigate the disaster, said that the plane broke up in mid-air, but declined to suggest any reasons.
With some Egyptian officials announcing they believe a technical failure is the most likely cause, criticisms have begun to appear in the Russian press of the country's low-cost charter airlines and their alleged willingness to cut-corners on safety.