In Omdurman, the largest city in Sudan, the Qadiriyya Sufi order meets every Friday outside Sheikh Hamed Al Nil mosque, which houses the tomb of their 19th century Sufi leader. (Photo by Ala Kheir, John Burns and Ibrahim Algrefwi/Brownbook)

A tractor trailer drives through flash flood waters that overran Skunk Creek, Tuesday, August 19, 2014, in northwestern Phoenix. Flooding from heavy rain in the Phoenix area has forced authorities to close several major roads, including a portion of Interstate 17 about 25 miles north of the city. (Photo by Matt York/AP Photo)

A P-51 Mustang named “Charlotte's Chariot” from the Southern Heritage Air Foundation flies past a cloud of smoke and fire from a nearby battle reenactment during the Wings Over Houston Airshow in Houston, on Saturday, November 1, 2014. Battle reenactments are part of the yearly show held at Ellington Airport. (Photo by Kar Hlava/AP Photo/Bay Area Citizen)

In this November 17, 2014 photo, Pancho, a domesticated huitia, confronts a camera, in Bainoa, Cuba. With their rope-like, dark tails, long front teeth, and whiskers that appear to be vibrating, huitias look like giant rats. They measure nearly a foot long (about 30 centimeters), with the largest ones weighing in bigger than a small dog. (Photo by Ramon Espinosa/AP Photo)

“The National Portrait Gallery, London's annual photographic portrait prize was established in 2003 as the Schweppes Photographic Portrait Prize. In the years 2006 and 2007 it was referred to simply as the Photographic Portrait Prize, while from 2008 new sponsors have resulted in the name, Taylor Wessing Photographic Portait Prize”. – Wikipedia. Photo: “Tic Tac and Tootsie (twin sisters Carrol and Shelly McKean)”. Taylor Wessing photographic portrait prize 2010. (Photo by Jeffrey Stockbridge)

A girl lights a candle as she marks the anniversary of 2015 Nepal earthquake, at Boudhanath stupa in Kathmandu, Nepal April 25, 2017. (Photo by Navesh Chitrakar/Reuters)

This picture taken on May 23, 2017 shows visitors posing for photos along a path at an Indonesian hamlet dubbed “the rainbow village” in Semarang, central Java, that has become an internet sensation and attracting hordes of visitors. (Photo by Suryo Wibowo/AFP Photo)