Singer Rihanna performs at the Staples Center on June 28, 2011 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)

Five year old Michael Esteban and his mother Kari Esteban, crawl through a 40-foot long, 4-foot high replica of a human colon on July 11, 2003 in Seattle. The colon is used to educate people on colorectal cancer. (Photo by Ron Wurzer/Getty Images)

Models promote a condom brand at the first Shenzhen s*x Culture Festival on September 21, 2007 in Shenzhen of Guangdong Province, China. The festival aims to increase awareness about reproductive health and popularise s*x education. (Photo by China Photos/Getty Images)

Female panda Tian Tian makes her first appearance in front of the media since arriving from China on December 12, 2011 in Edinburgh, Scotland. (Photo by Jeff J. Mitchell/Getty Images)

Actor Woody Harrelson and actress Sofia Vergara onstage during the 69th annual Golden Globe Award Nominations announcements at The Beverly Hilton hotel on December 15, 2011 in Beverly Hills, California. (Photo by Kevin Winter/Getty Images)

A man walks on the Cobb as storm waves break behind on December 13, 2011 in Lyme Regis, England. (Photo by Matt Cardy/Getty Images)

Burmese monks take their yearly exam December 13, 2011 in Bago, Myanmar. Around 1,400 monks from Bago province took part . (Photo by Paula Bronstein /Getty Images)

North Korean soldiers look at South Korea across the Korean Demilitarized Zone (DMZ), on December 22, 2011 in Panmunjom, South Korea. (Photo by Chung Sung-Jun/Getty Images)