Members of a teenage girl gang convincing an unwilling recruit to join the gang, circa 1955. (Photo by Vecchio/Three Lions)

A boat commutes across the Mekong river in Phnom Penh on August 8, 2014. The Mekong is the world's twelth longest river running from the Tibetan Plateau through China's Yunnan province, Myanmar, Laos, Thailand, Cambodia and Vietnam. (Photo by Tang Chhin Sothy/AFP Photo)

UConn students from Storrs, Conn., Gary Tu, Danny Wang and Victor Zheng, fish at Shenipsit Lake in Tolland, Conn. during sunset on Tuesday, August 19, 2014. (Photo by Jim Michaud/AP Photo/Journal Inquirer)

The first red panda cub was born on May 30 in zoo Zlin. Zoologist Roman Vrzal holds a male of red panda. The Red panda is pictured in Zlin, Czech Republic, August 20, 2014. (Photo by Dalibor Gluck/CTK)

Movement is the essence and meaning of our life. We feel so much more alive when we are in motion, while people who spend hours motionless tend to have trouble connecting with the outside world. Whether you dive from a high cliff, play your favorite sport, dance at a rave party, or simply walk down a path with autumn leaves rustling under your feet with the love of your life by your side, all those things make your life richer, more beautiful, and more fulfilling. This set of pictures beautifully captures the joy of never-ending motion that enriches our life. (Photo by Brian Snyder/Reuters)

People take pictures of the sunset in Berlin October 27, 2014. (Photo by Hannibal Hanschke/Reuters)

A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

Snow covers roofs, streets and the Charles River following a winter blizzard in Boston, Massachusetts January 28, 2015. A powerful blizzard struck Boston and surrounding New England on Tuesday, leaving some 4.5 million people grappling with as much as three feet of snow and coastal flooding. (Photo by Brian Snyder/Reuters)