A giant river otter, the world's largest otter species, looks out of its enclosure at the newly completed River Safari in Singapore, on March 25, 2013. (Photo by Wong Maye-E/Associated Press)

These photographs of hundreds of ducks following their leader down a river are truly mesmerizing. Rafeur Rahman of Bangladesh climbed a high bridge and saw hundreds of ducks apparently playing a game of follow the leader. More than 500 ducks live on the river, where the mosses and snails provide the perfect habitat. Here: Ducks in the river Baral in Bangladesh. (Photo by Rafeur Rahman/Caters News Agency)

A man performs ablution using water at an old fountain before performing prayers in the old city of Algiers Al Casbah, Algeria December 3, 2015. The Algiers Casbah is a UNESCO World heritage site that includes the Sidi Ramdane mosque and former fortress, 10 centuries old. Decay from the passing years, as well as earthquake damage in 2003, leads some to consider a move to modern apartments with financial backing from the government. Others refuse to leave a neighbourhood they have called home for decades. (Photo by Zohra Bensemra/Reuters)

A Hindu holy man or Sadhu walks back to his ashram after taking a dip at Sangam, confluence of Ganges river, Yamuna river and mythical Saraswati river in Allahabad, India, Thursday, August 4, 2016. (Photo by Rajesh Kumar Singh/AP Photo)

An Iraqi man comforts his 4-year-old son at a regroupment center for POWs of the 101st Airborne Division near An Najaf, Iraq, March 31, 2003. The man was seized in An Najaf with his son and the U.S. military did not want to separate them. (Photo by Jean-Marc Bouju/Associated Press)

Members of the Black Hebrews community celebrate the Shavuot harvest festival on June, 19, 2011 in Dimona, Israel. The community, who call themselves the African Hebrew Israelites of Jerusalem, moved to Israel in 1969 from the United States and have since maintained a vibrant culture which includes a communal lifestyle and a vegan diet. They are not recognized as Jews by Israel despite their belief in the Torah, but were granted permanent resident status in 2003. (Photo by Uriel Sinai/Getty Images)

Since 2003, photographer Sergey Fomin has been shooting Russia’s most attractive natural, historical, and architectural objects from different aircrafts. Photo: “An Explosive Scene”. The 1,486-meter-high Karymskii Volcano in Kamchatka. (Photo by Sergey Fomin)

A Thai devotee in a state of trance screams while holy water is sprayed as thousands race towards the edifice of the founder monk during the annual Tattoo fesitval at Wat Bang Phra on March 7, 2009 in Nakhom Pathom, Thailand. Some men take on the characteristics of sacred animals that have been carved onto their skin. Thousands of believers from all over Thailand come to take part in one of the country's most bizarre festivals about 50 miles outside Bangkok to pay respect to the temple's monks who are master tattooist. In Thai culture the tattoo or Thai word sak yant is worn as a symbol of spiritual and physical protection, many believe that the tattoo have mystical powers. Many tattoo fanatics choose to have monkeys and tigers as well as the Khmer/Cambodia ancient script on their bodies. (Photo Paula Bronstein/Getty Images)