SOME FLASH MOBS dance, some flash mobs sing. In Russia, a flash mob sends paper lanterns up into the night sky.

Flash mobs — groups of people who gather suddenly and unannounced in a public place to perform together — have spread worldwide. In South Africa, a singing flash mob delights shoppers in a mall. In China, a dancing flash mob celebrates Michael Jackson. In the U.S., flash mobs not only sing and dance but do gymnastics and even propose marriage to their loved ones.

In the Russian city of St. Petersburg, a time-exposure photograph catches the tracks of hundreds of paper lanterns launched by a flash mob. Lit with small candles, the lanterns drift skyward in front of one of Russia's iconic churches, the Church of Our Savior on Spilled Blood.

The church's name bears witness to the city's bloody history; it commemorates the site where Czar Alexander II was assassinated in 1881. Russia's 20th-century violence then swirled around the church. It was ransacked after the 1917 Russian Revolution; closed by Soviet communist rulers and used as a warehouse; and damaged during the Nazis' Siege of Leningrad (as St. Petersburg then was called) in World War II. Hundreds of thousands of civilians starved to death, and German bombardments scorched the city.

Now the church, restored and reopened in the late 1990s, is thronged with tourists from all over the globe. And outside, the lanterns drift into the sky, a peaceful echo of St. Petersburg's fiery past.

Kristin R. Jackson is The Seattle Times' NWTraveler editor. Contact her at kjackson@seattletimes.com.