The flame, which spiritual leaders say has been continuously lit for more than 1,200 years, was salvaged after the blaze and moved to a different site.

For centuries, the bones of some six million people were buried in the catacombs beneath the city. Curators are trying to preserve and modernize the tunnels while maintaining the spooky ambience.

With political activism off-limits, residents of St. Petersburg are finding purpose and community in the “politics of small deeds,” repairing and cleaning architectural treasures.