An arrow-head discovered in 2006 by Archaeologists of the University of Cambridge Archaeological Unit, is displayed by one of the team uncovering Bronze Age wooden houses, preserved in silt, from a quarry near Peterborough, Britain, January 12, 2016. Archaeologists said on Tuesday they had discovered what were believed to be the best-preserved Bronze Age dwellings ever found in Britain, providing an extraordinary insight into prehistoric life from 3,000 years ago. (Photo by Peter Nicholls/Reuters)

Syrian rescue workers and residents help an injured woman following a reported air strike by government forces on the rebel-held neighbourhood of Haydariya in the northern city of Aleppo on April 10, 2016. (Photo by Thaer Mohammed/AFP Photo)

People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

Cuban migrant Yamilen Arbelo, 40, walks down a hill as she crosses the border from Colombia through the jungle into La Miel, in the province of Guna Yala, Panama November 29, 2015. According to local authorities in La Miel, some 100 to 150 Cubans have been entering Panama from Colombia every day for the last three months. Scores of Cubans have come to Panama as they seek overland passage towards the United States fearing a recent detente between Washington and Havana could end their preferential treatment. (Photo by Carlos Jasso/Reuters)

An old toilet is displayed during the “Toilet!? Human Waste and Earth's Future” exhibition at The National Museum of Emerging Science and Innovation – Miraikan on July 1, 2014 in Tokyo, Japan. The exhibition focuses on how the toilet has changed our daily lives and discovers what the most environment-friendly and ideal toilet is. (Photo by Keith Tsuji/Getty Images)

Women pose for a photograph in traditional Ethiopian dress during the annual Timkat Epiphany celebration on January 19, 2017 in Gondar, Ethiopia. Timkat is the Ethiopian Orthodox Christian festival which celebrates the baptism of Jesus in the Jordan river. During the festival, Tabots, or models of the Ark of the Covenant, are taken from churches around Gondar and paraded through the streets to Fasilides Bath. (Photo by Carl Court/Getty Images)

Freida Pinto as Jas Mitra in Showtime's “Guerrilla”, 2016. (Photo by Sky UK Limited/SHOWTIME)

Models of the SibPlus Models agency and participants of the Miss Doughnut beauty competition take part in a rehearsal in Krasnoyarsk, Siberia, Russia, March 4, 2017. (Photo by Ilya Naymushin/Reuters)