Riot police officers in position to crack down on demonstrators during a protest against Venezuelan President Nicolas Maduro, in Caracas on April 20, 2017. Venezuelan riot police fired tear gas Thursday at groups of protesters seeking to oust President Nicolas Maduro, who have vowed new mass marches after a day of deadly unrest. Police in western Caracas broke up scores of opposition protesters trying to join a larger march, though there was no immediate repeat of Wednesday's violent clashes, which left three people dead. (Photo by Juan Barreto/AFP Photo)

Iraqi soldiers from 9th Armoured Division give drops of water to a dehydrated child rescued earlier by soldiers at the frontline, during the ongoing fighting between Iraqi forces and Islamic State militants near the Old City in western Mosul, Iraq June 13, 2017. (Photo by Erik De Castro/Reuters)

Indian children help to push an auto rickshaw along a flooded street after heavy rain in Jalandhar on June 29, 2017, as the monsoon season begins. (Photo by Shammi Mehra/AFP Photo)

A newly born Sitatunga calf seen at ZSL Whipsnade Zoo on November 24, 2016 in Whipsnade, England. The swamp-dwelling species, also known as a marshbuck, is Africa's only true amphibious antelope. It was snuggled up in the leaves and almost perfectly camouflaged as it mother tended it. (Photo by Tony Margiocchi/Barcroft Images)

People wearing bear fur costumes dance during the annual bear ritual gathering in Comanesti, Romania, Friday, December 30, 2016. In pre-Christian rural traditions, dancers wearing colored costumes or animal furs, toured from house to house in villages singing and dancing to ward off evil, in the present the tradition has moved to Romania's cities too, where dancers travel to perform the ritual for money. (Photo by Vadim Ghirda/AP Photo)

Models wait backstage during Ukrainian Fashion Week in Kiev, March 17, 2016. (Photo by Gleb Garanich/Reuters)

Idols of the Hindu god Ganesh, the deity of prosperity, are transported to places of worship on the first day of the Ganesh Chaturthi festival in Mumbai, India, September 5, 2016. (Photo by Danish Siddiqui/Reuters)

A Catholic priest blesses a grave, marking All Saints' Day as the people stand next to monument partially destroyed by an old fallen tree at a cemetery in the village of Zubkovo, 150 km (93 miles) west of Minsk, Belarus, Wednesday, November 1, 2017. Belarusian Catholics marked All Saints Day by visiting graves of their relatives. (Photo by Sergei Grits/AP Photo)