News personality Katie Couric, left, Jenna Dewan-Tatum, center, and model Chrissy Teigen mingle during the White House Correspondents' Association dinner at the Washington Hilton on Saturday, April 25, 2015, in Washington. (Photo by Evan Vucci/AP Photo)

Revelers take a selfie during a Holi Festival in Madrid, Spain, Sunday, April 26, 2015. The festival is based on the Hindu spring festival Holi, also known as the festival of colours where participants colour each other with dry powder and coloured water. (Photo by Andres Kudacki/AP Photo)

A florist waits for customers at the Piedra Liza flower market in Lima April 29, 2015. The market sells flowers that come from all over Peru. Peru is home to more than 25,000 varieties of flowering plants like geraniums, carnations, roses, hydrangeas and jasmine, according to local media. (Photo by Mariana Bazo/Reuters)

A tea garden worker plucks tea leaves inside Aideobarie Tea Estate in Jorhat in Assam, India, April 21, 2015. Unrest is brewing among Assam's so-called Tea Tribes as changing weather patterns upset the economics of the industry. Scientists say climate change is to blame for uneven rainfall that is cutting yields and lifting costs for tea firms. (Photo by Ahmad Masood/Reuters)

An African immigrant tries to jump a fence into a ferry terminal in the western Greek town of Patras April 28, 2015. Afghan, Iranian and Sudanese immigrants, living precariously in abandoned factories in Patras, southwest Greece, try to stow away on nearby ferries to Italy as they seek a better life in Europe beyond crisis-hit Greece. (Photo by Yannis Behrakis/Reuters)

James Spears takes his 1964 German built Amphicar for a drive on Lake Mead in Nevada May 6, 2015. Its a journey many drivers dream of, rather than travelling round a lake simply driving through it. But for James Spears it may be time to make the most of the waters in Lake Mead in Nevada, as water levels are plunging as California struggles to cope with a fourthsuccessive year of droughts. (Photo by Mike Blake/Reuters)

A visitor kneels on the 180-meter-high and 300 meter-long glass-bottomed suspension bridge at the Shiniuzhai National Geopark in Pingjiang county, in central China's Hunan province, 24 September 2015. (Photo by Jiao Zi/Imaginechina via AFP Photo)

Joel said documenting the Kazakh nomad summer migration was really an epic journey – a time travel journey – and at the same time was possible to get an understanding of how the balance of nature is still possible in Altai Mountains, Mongolia, June 2015. (Photo by Joel Santos/Barcroft Images)