Photographer Andy Hall joins the thousands of fans from west Africa who have gathered for Baaba Maal's annual Blues du Fleuve festival in Senegal. Here: Dancers wait to perform on stage. (Photo by Andy Hall/The Observer)

A passenger not wearing pants sits in a subway train during the “No Pants Subway Ride” in Prague, Czech Republic, January 10, 2016. The event is an annual flash mob and occurs in different cities around the world in January, according to its organisers. (Photo by David W. Cerny/Reuters)

Kimono-clad young women take their selfies near a venue during the Coming of Age Day celebration ceremony in Yokohama, Japan on January 9, 2023. (Photo by Kim Kyung-Hoon/Reuters)

“The 8th annual Water War on Friday in the center of Tel-Aviv, Israel turned into a battlefield, quite literally. As two thousand people were having fun in the square, some water-fighters took to more radical behavior, targeting passing cars, motorcycles and public buses”. – iReport.cnn.com (Photo by Sergey Demyanchuk)

U.S. Army Sgt. Patricia Foust receives a free Christmas tree on December 7, 2011 at Fort Carson in Colorado Springs, Colorado. More than 600 soldiers and military families at the base chose trees as part of the annual Trees for Troops program. (Photo by John Moore/Getty Images)

Controlled fires lit by residents glow in the hills over the village of Pottenstein during the annual Epiphany celebration on January 6, 2012 in Pottenstein, Germany. The ceremony, which also includes a procession with torches through the village center, is part of a tradition going back to 1905. Pottenstein was once a pilgrimage destination. (Photo by Johannes Simon/Getty Images)

English Lop Eared Rabbits on the judging table on January 28, 2012 in Harrogate, England. Approximately 3,000 animals attend the annual show, which runs over two days and was first held in 1921. The Rabbit Grand National, attracts competitors from as far afield as Sweden to Yorkshire. (Photo by Bethany Clarke/Getty Images)

A woman smokes marijuana during a Global March for Marijuana in Medellin, Colombia, May 5, 2018. The annual Global Marijuana March is taking place in over 100 cities across the world in an effort to raise awareness of the benefits of medical cannabis and to call for the legalization of marijuana. (Photo by Fredy Builes/Reuters)