Participants hold red scarves as they celebrate the “Chupinazo” marking the start at noon sharp of the San Fermin Festival at Castle square in Pamplona, northern Spain on July 6, 2013. Ten of thousands of people packed Pamplona's streets for a drunken kick-off to Spain's best-known fiesta: the nine-day San Fermin bull-running festival. (Photo by Pedro Armestre/AFP Photo)

A competitor poses before the Tough Guy Challenge endurance race on January 27, 2013 in Telford, England. Every year thousands of people run the 8 mile assault course which involves freezing temperatures, fire and ice. (Photo by Michael Regan)

An infrared portrait from NASA's Spitzer Space Telescope which shows generations of stars is seen in this undated NASA handout image released February 14, 2013. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Red shows heated dust that pervades the region's cavities, while green highlights dense clouds. (Photo by NASA/Reuters/JPL-Caltech/Harvard-Smithsonian/Handout)

Toyota revealed its i-Road concept, a three-wheeled all-electric motorcycle of sorts that seats two. The unique design is only 33 inches wide, which would make it tops in buzzing in through and around traffic. An Active Lean system tilts the i-Road through corners like a motorbike, while the cabin (which seats two in a tandem layout) is fully enclosed. Maximum range is about 30 miles. (Photo by Luis Fernando Ramos/G1)

A schoolgirl collects rubbish from Karachi's Clifton beach early morning April 22, 2013, during a cleaning campaign as part of the commemoration of Earth Day. (Photo by Akhtar Soomro/Reuters)

First lady Michelle Obama (R), joined by daughters Sasha Obama (C) and Malia Obama, is presented with the official White House Christmas Tree on November 25, 2011 in Washington, DC. The tree, a 19-foot-tall balsam fir, was grown on Schroeder's Forevergreens farm near Neshkoro, Wisconsin. (Photo by Brendan Hoffman/Getty Images)

U.S. Army Sgt. Patricia Foust receives a free Christmas tree on December 7, 2011 at Fort Carson in Colorado Springs, Colorado. More than 600 soldiers and military families at the base chose trees as part of the annual Trees for Troops program. (Photo by John Moore/Getty Images)

A resident types a text message on her mobile phone, as she sits on a bench made from a tree, which is a creation by Brazilian artist Hugo Franca at Largo da Batata square in Sao Paulo March 17, 2015. Franca, a designer from Sao Paulo is working with the city to make use of fallen trees to turn them into sculpture furniture to line the city's parks, streets and plazas. Brazil's largest city was slammed by several strong storms this rainy season that brought with them heavy rain, lightning and winds as high as 90 kilometres (55 miles) per hour. (Photo by Nacho Doce/Reuters)