The BMW i8 concept vehicle is displayed at a sneak preview of the car along with the BMW i3 on November 9, 2011 in New York City. (Photo by Spencer Platt/Getty Images)
LOS ANGELES, CA - NOVEMBER 17: The BMW i8 plug-in hybrid all-electric concept car makes its North American debut at the Los Angeles Auto Show on November 17, 2011 in Los Angeles, California. The car show opens to the public tomorrow and runs through November 27. (Photo by Kevork Djansezian/Getty Images)
In this April 23, 2015 photo, friends Jia Haixia, left, and Jia Wenqi work to plant a tree in a field in Yeli village near Shijiazhuang city in northern China's Hebei province. For the past 13 years, Jia Wenqi, who has no arms, and Jia Haixia, who is blind, have worked together to plant and water more than 12,000 trees near their village. (Photo by Helene Franchineau/AP Photo)
An autumn leaf sticks to a bench near the Bishops Castle near Wells Cathedral on November 1, 2011 in Wells, England. According to a number of nature watchers the autumn colours are currently reaching their peak following an unusually warm September and October which has led to trees holding onto their leaves longer than normal. (Photo by Matt Cardy/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)