Pham Thi Thanh drinks a glass of water used as a treatment during a medium ritual at a Hau Dong ceremony at Phu Day temple in Nam Dinh province, Vietnam, May 7, 2017. Dating to the 16th century, Hau Dong centres on a belief in the Mother Goddesses of three realms – forest, water and heaven. It draws from elements of Taoism, Buddhism and other religions. (Photo by Reuters/Kham)

A labourer packs incense in preparation for Tet, the traditional Vietnamese lunar new year, in Hong Chau village, outside Hanoi January 29, 2015. Tet is from February 14 till 24. (Photo by Reuters/Kham)

Children wave Vietnamese and American flags while waiting for arrival of U.S. President Barack Obama (not pictured) before a welcoming ceremony at the Presidential Palace in Hanoi, Vietnam May 23, 2016. (Photo by Reuters/Kham)

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 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)

This image taken from video provided by TVBS shows a commercial airplane clipping an elevated roadway just before it careened into a river in Taipei, Taiwan, Wednesday, February 4, 2015. The ATR-72 prop-jet aircraft had 58 people aboard. (Photo by AP Photo/TVBS)

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)