A man looks at members of the flash mob group calling themselves the «Brides of March» (“Grab a wedding dress and join the brides as we parade through the heart of San Francisco, strolling through Union Square, shopping at fancy stores and drinking at local bars!”) as they stand outside a bar March 18, 2006 in San Francisco. The flash mob group made their way through the streets stopping at bars, cafes, and several stores. (Photo by Justin Sullivan/Getty Images)

Visitors to Kensington Gardens are reflected in Anish Kapoor's sculpture “C-Curve 2007” on September 27, 2010 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Beluga the bog poses as Britney Spears during the 17th annual Tompkins Square Halloween Dog Parade October 28, 2007 in New York City. The event is the largest dog Halloween party in the United States with an annual attendance of over 400 costumed dogs. (Photo by Mario Tama/Getty Images)

Singer/Songwriter Chris Janson (center black shirt) with fans during Country Thunder USA – Day 3 on April 11, 2015 in Florence, Arizona. (Photo by Rick Diamond/Getty Images for Country Thunder USA)

Fireworks illuminate the sky over downtown Seoul during the International fireworks festival 2007 at Han River on October 13, 2007 in Seoul, South Korea. The United States, Japan and South Korea have team was attending the festival. (Photo by Chung Sung-Jun/Getty Images)

Children watch their classmate pour cold water on herself under the watch of a fitness coach at a local kindergarten in Russia's Siberian city of Krasnoyarsk, March 11, 2015. The program, which also involves sports training and sauna usage, has been practiced by the kindergarten for more than 15 years as they believe it has health benefits and keeps the children fit. Children start pouring cold water on themselves outdoors after about three years of training and undergoing medical tests, and the kindergarten is the only one in the region that practices these exercises, according to employees. (Photo by Ilya Naymushin/Reuters)

Samurai commiting seppuku (hara-kiri) in Japan, circa 1880. (Photo by adoc-photos/Corbis via Getty Images)

Finding just the right spot above the clouds at Camp 1 on Ama Dablam, Danuru Sherpa uses his iPhone to catch up with friends and family. Even at 18,500 feet (5,654 meters), climbers here can check their email and other dispatches from the world below. (Photo by Aaron Huey/National Geographic)