Event curators Harry Parr (L) and Sam Bompas (R) sit in paddle boats in the Truvia Voyage of Discovery installation on the roof of Selfridges department shop on July 21, 2011 in London, England. Selfridges is opening its roof to the public for only the second time since WW2 to host the installation, which includes a boating lake with dyed water and bar. (Photo by Matthew Lloyd/Getty Images)

Revelers celebrate the Indian festival of Holi on the deck of the ship Peking at South Street Seaport in Manhattan March 19, 2011 in New York City. The Hindu festival of Holi , also known as the Festival of Colors, marks the arrival of spring where participants throw colored powder and water on one another. Many of the New York participants are Indian-American.

People protect themselves behind a trash can as anti-riot olice fires water cannon to disperse thousands of people demonstrating following the death of Berkin Elvan, a teenage boy wounded in mass anti-government demonstrations last year, on March 11, 2014 near the Middle East Technical University (ODTU) in Ankara. Elvan's story – he spent 269 days in a coma – gripped the nation and became a symbol of the heavy-handed tactics used by police to reign in the biggest demonstrations against Prime Minister Recep Tayyip Erdogan since he came to power in 2003. (Photo by Adem Altan/AFP Photo)

This image provided by NASA shows parts of Europe and Africa very easily recognizable in this night time image shot by one of the Expedition 25 crew members aboard the International Space Station flying 220 miles above Earth on Thursday October 28, 2010. The view “looks” northward over Sicily and the “boot” of Italy, with the Mediterranean Sea representing most of the visible water in the view and the Adriatic Sea to the right of center. Tunisia is partially visible at left. Part of a docked Russian spacecraft and other components of the ISS are in the foreground. (Photo by AP Photo/NASA)

A submerged statue of the Hindu Lord Shiva stands amid the flooded waters of river Ganges at Rishikesh in the Himalayan state of Uttarakhand June 17, 2013. Early monsoon rains have swollen the Ganges, India's longest river, swept away houses, killed at least 60 people and left tens of thousands stranded, officials said on June 18, 2013. (Photo by Reuters/Stringer)

A swimmer stops short of a red algae bloom at Sydney's Clovelly Beach on November 27, 2012, which closed some beaches for swimming including Bondi Beach for a period of time. While the red algae, known as Noctiluca scintillans or sea sparkle, has no toxic effects, people are still advised to avoid swimming in areas with discoloured water because the algae, which can be high in ammonia, can cause skin irritation. (Photo by William West/AFP Photo)

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)

In this March 21, 2015 photo, 15-year-old Guerline Augustin carries river water on her head, back to a borderland encampment outside the southeast Haitian town of Anse-a-Pitres, Haiti. The encampment is filled with people who either fled or were forcibly removed from the neighboring Dominican Republic amid an immigration crackdown. Within the next month, authorities hope to move nearly 2,400 people out of six encampments by providing subsidies for them to rent homes for a year in southeastern Haiti. The International Organization for Migration is coordinating the effort with $2 million from a U.N. emergency fund. (Photo by David McFadden/AP Photo)