David Reutimann, driver of the #00 Aaron's Dream Machine Toyota, Brian Vickers, driver of the #83 Red Bull Toyota, and Denny Hamlin, driver of the #11 FedEx Express Toyota, collide after an incident in the NASCAR Sprint Cup Series Jeff Byrd 500 Presented By Food City at Bristol Motor Speedway on March 20, 2011 in Bristol, Tennessee.

A CRH train is seen passing through Nanjing South Railway Station, which is part of the Beijing-Shanghai High-Speed Railway Line, on March 27, 2011 in Nanjing, Jiangsu Province of China. The High-Speed railway line is 1,318 kilometres long, running between Beijing and Shanghai. The line will open on June 10, 2011. (Photo by ChinaFotoPress/Getty Images)

Victoria's Secret angels Adriana Lima, Candice Swanepoel, Alessandra Ambrosio and Miranda Kerr arrive at the 2011 Victoria's Secret SWIM Collection Pink Carpet Event hosted by VS Angels at Club L on March 30, 2011 in Los Angeles, California. (Photo by Jerod Harris/Getty Images for Victoria's Secret)

A humanoid dental patient robot, named Hanako Showa, about to be used during a demonstration of dental treatment at Showa University on March 25, 2010 in Tokyo, Japan. The robot was co-developed by the university and tmsuk co. Ltd, and simulates real human patients. The robot has been used for training of procedures in which the dental treatment requires a high level of precision. (Photo by Koichi Kamoshida/Getty Images)

Taronga Zoo's elephant baby, as yet unnamed, is seen at Taronga Zoo on March 12, 2010 in Sydney, Australia. The Asian Elephant calf has continued to make progress following a protracted labour that spanned six days. The calf was originally believed to have died in the womb during labour but surprised veterinarians and zoo staff with an unexpected delivery early Wednesday morning. (Photo by Bobby-Jo Vial/Taronga Zoo via Getty Images)

A protester wears a pig mask as he marches through the streets of downtown Vancouver with thousands of people participating in the Occupy Vancouver protest on October 15, 2011 in Vancouver, British Columbia, Canada. Thousands of people are taking to the streets in cities across the world today in demonstrations inspired by the Occupy Wall Street protest in New York City. An estimated 2,000 people participated in the Vancouver occupation. (Photo by Jeff Vinnick/Getty Images)

Visitors and tourists walk around the ancient monument at Stonehenge on March 2 2012 in Wiltshire, England. The English Heritage, managed prehistoric UNESCO World Heritage site, believed to have been constructed in 3000BC, has always been a “must see” attraction for visitors to the UK and it is hoped that it will remain so for visitors to the London 2012 Olympic Games this summer. (Photo by Matt Cardy/Getty Images)

Crowd members attempt to keep dry with umbrellas and ponchos prior to the 2012 Sydney Gay & Lesbian Mardi Gras Parade on March 3, 2012 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)