Pamukkale, Turkey, is home to these terrace pools, formed by the build-up of carbonate mineral from the warm water flowing from the thermal springs above. (Photo by Image Courtesy of Jennifer Hayes/Getty Images)

Four pillars of light from the 4 Laser Guide Star Facility on ESO's Very Large Telescope (VLT) are shown reaching into the Chilean night sky in this image from ESO Photo Ambassador Fred Kamphues, on September 2, 2016. The lasers are a key part of the adaptive optics system on the VLT. Adaptive optics allows astronomers to drastically reduce the atmospheric distortion present at even the best sites in the world for astronomy, including Paranal in Chile, the home of the VLT. (Photo by F. Kamphues/ESO)

Revellers celebrate "Ash Monday" by participating in a colourful "flour war", a traditional festivity marking the end of the carnival season and the start of the 40-day Lent period until the Orthodox Easter,in the port town of Galaxidi, some 215 km (134 miles) north west of Athens, March 18, 2013. The revellers "fight" by throwing coloured flour, charcoal dust and powder painting until they essentially run out of supplies. (Photo by Yannis Behrakis/Reuters)

Mohamed Mostafa, 35, carries dyed yarns at a dye workshop in old Cairo, Egypt, March 17, 2016. Egypt's hard currency crisis and competition from modern factories in Asia and at home threaten one of the last dye workshops in Egypt. But one of its owners takes comfort in the trade's ancient resilience. Mohamed Mostafa boasts that the profession dates back 3,000 years, so it can survive anything. (Photo by Amr Abdallah Dalsh/Reuters)

“These dolly birds are showing off the latest haute COO-ture in a stunning set of images that portray everyday pigeons as fashion models. The series, titled “Darwin’s Pigeons”, was snapped by British photographer Richard Bailey, who was looking to capture the birds’ photogenic side as a tribute to the Father of Evolution himself, who it is believed was fascinated by the birds”. – Caters News. Photo: Old Dutch Capucine. Darwin’s Pigeons series. (Photo by Photo by Richard Bailey/Caters News)

In this photo made late Saturday, August 9, 2014, in Keelung, Taiwan, a traditional Chinese dance troupe performs during a parade marking the beginning of the Chinese folklore's mid-summer's Ghost Month Festival. Fourteen days into the seventh month of the lunar calendar, August 9, in 2014, marks the traditional Chinese Ghost Month where the gates of the underworld are opened and spirits of the deceased are set free to roam the world of the living. The month long festivities are aimed to please the roaming spirits. (Photo by Chiang Ying-ying/AP Photo)

People are seen in the crowd as Serbian Emir Kusturica & The No Smoking Orchestra performs during the third day of the Mexican musicial festival Vive Latino, at the Foro Sol in Mexico City, on March 29, 2014. (Photo by Alfredo Estrella/AFP Photo)

A couple stands next to a poster depicting Dutch politician Geert Wilders and Russian President Vladimir Putin kissing, at a metro station in Amsterdam April 3, 2016. (Photo by Cris Toala Olivares/Reuters)