Giant Olympic rings are towed on The River Thames past The Tower of London on February 28, 2012 in London, England. (Photo by Peter Macdiarmid/Getty Images)

An alligator is pictured stuck in the mud of the dry Pilcomayo river, which is facing its worst drought in almost two decades, on the border between Paraguay and Argentina, in Boqueron, July 3, 2016. (Photo by Jorge Adorno/Reuters)

Workers use a boat to recover supplies from a flooded grain elevator May 4, 2011 in Caruthersville, Missouri. Heavy rains have left the ground saturated, rivers swollen, and has caused widespread flooding in Missouri, Illinois, Kentucky and Arkansas. (Photo by Scott Olson/Getty Images)

Spectators are swept by huge waves while watching tides of Qiantang River at a dike on August 31, 2011 in Haining, Zhejiang Province of China. More than 20 spectators were injured by strong tides as the typhoon Nanmadol approached on Wednesday. (Photo by ChinaFotoPress/Getty Images)

An Orthodox Christian child is baptized during Epiphany celebrations in the Jordan River January 19, 2012 at the Qasir al-Yahud baptismal site near Jericho, in the West Bank. Thousands of pilgrims gathered for the annual celebration at the site that the Eastern churches believes Jesus was baptised by John. (Photo by Uriel Sinai/Getty Images)

Water gushes out from the Xiaolangdi Reservoir on the Yellow River during a sand-washing operation on June 20, 2012 in Luoyang, China. The sand-washing operation, which started on June 19 and will last for about 20 days, is conducted to clear out the silt deposits at the dam. (Photo by China Foto Press)

South Korean soldiers participate in a winter river crossing operation in preparation for a possible North Korean attack on February 8, 2012 in Yeoju, South Korea. The Korean peninsula is the world's last Cold War frontier as stalinist North Korea and pro-western South Korea have been technically at war since the 1950-53 conflict. (Photo by Chung Sung-Jun/Getty Images)

In this photo taken Wednesday, April 30, 2014, a dragonfly sits on the nose of a Gharial, rare crocodile-like creatures, in the River Chambal near Bhopepura village in the northern Indian state of Uttar Pradesh. The narrow 250-mile stretch of the Chambal is a place of crocodiles and jackals, of river dolphins and the occasional wolf. Hundreds of species of birds, storks, geese, babblers, larks, falcons and so many more, nest along the river. Endangered birds lay small speckled eggs in tiny pits they dig in the sandbars. Gharials, rare crocodile-like creatures that look like they swaggered out of the Mesozoic Era, are commonplace here and nowhere else. (Photo by Altaf Qadri/AP Photo)