In this two photo combination picture, the Eiffel Tower with its usual lighting at left, and after the lighting was switched off at right, at the occasion of the Earth Hour, in Paris, France, Saturday March 28, 2015. This Saturday, 28 March 8:30 p.m. local time, individuals, businesses, cities and landmarks around the world are switching off their lights for one hour to focus attention on climate change. (Photo by Remy de la Mauviniere/AP Photo)

A solar-powered plane takes off from Jiangbei International Airport in southwest China's Chongqing Municipality, Tuesday, April 21, 2015. The Solar Impulse 2 departed Chongqing on Tuesday for a 1190-kilometer (642-mile) flight to the city of Nanjing in eastern China, the sixth leg of its around-the-world flight. (Photo by Chinatopix via AP Photo)

A Palestinian youth practices his Parkour skills over the ruins of houses, which witnesses said were destroyed during a seven-week Israeli offensive, in the Shejaia neighborhood east of Gaza City October 1, 2014. Some Palestinian youths aged between 13 and 17 years old, train in the devastated area as a personal initiative to develop their skills. Parkour is a physical discipline of movement focused on overcoming obstacles. (Photo by Mohammed Salem/Reuters)

This picture taken on November 1, 2014 shows Japanese body-painting artist Hikaru Cho (L) adding the finishing touches to a body painting of fingers sticking out from prison cell bars on the head of Ryonosuke Tanaka during “Tokyo Designers Week” in Tokyo. Cho, 21, was born to Chinese parents in Japan and burst onto Tokyo's art scene when she entered the city's Musashino Art University in 2012. Cho's ultimate ambition is to paint an entire – and naked – body. (Photo by Yoshikazu Tsuno/AFP Photo)

Two brides kiss during their wedding ceremony to each other at the wedding registry office in St. Petersburg November 7, 2014. The two St. Petersburg women married in the official city ceremony last week, seemingly circumventing Russia's ban on same-s*x marriages. One of the brides was born a man but is undergoing hormone therapy and considers herself a woman. Though her male passport identity ensured the marriage was legal by Russian law, a St. Petersburg lawmaker has vowed to nullify their wedding. (Photo by Reuters/Stringer)

An aerial view of the Atibainha dam, part of the Cantareira reservoir, during a drought in Nazare Paulista, Sao Paulo state November 18, 2014. Brazil's worst drought in 80 years has left the Cantareira system, that provides greater Sao Paulo with most of its water, with the lowest water level on record, with daily rationing becoming common in the region's smaller cities, according to the state authorities and the two main reservoirs serving metropolitan Sao Paulo, South America's largest city, could dry out by February if relief does not arrive in the upcoming rainy season. (Photo by Nacho Doce/Reuters)

A man protesting the Ferguson grand jury decision to not indict officer Darren Wilson in the Michael Brown case is arrested while marching through the streets on December 1, 2014 in New York City. Brown, an 18-year-old black man, was killed by Darren Wilson, a white Ferguson, MO police officer, on August 9. (Photo by Andrew Burton/Getty Images)

A doll forms part of a sculpture as part of an exhibit titled The Sea Isn't Made for Fish at Rio de Janeiro Federal University in Rio de Janeiro, Brazil, Monday, June 1, 2015. Art students have taken advantage of a material they have in endless supply trash to create an exhibition that aims to draw attention to the fetid state of the citys Guanabara Bay, where the Olympic sailing events are to be held next year. (AP Photo/Silvia Izquierdo)