A visitor takes pictures with a smartphone of an artwork entitled “Blue Europe, 2015” by Chinese artist Liu Bolin, on display during the exhibition “Visible Invisible” at the Mudec Museum in Milan on May 14, 2019. Liu Bolin known as “the invisible man” for his photographic self-portraits, focused on a body-painting blending with the surrounding area. (Photo by Miguel Medina/AFP Photo)

When Dutch photographer Marcel Heijnen moved to Hong Kong, the territory’s shop cats instantly caught his eye. While the “feline emperors” are the stars, his shots also offer insights into Hong Kong’s wares, from dried fish to paper. Here: Hong Kong Shop Cats #17. (Photo by Marcel Heijnen/Blue Lotus)

View of the “Sunset Lake” hot spring with it's unique colors caused by brown, orange and yellow algae-like bacteria called Thermophiles, that thrive in the cooling water turning the vivid aqua-blues to a murkier greenish brown, in the Yellowstone National Park, Wyoming on June 1, 2011. Yellowstone National Park, was established by the U.S. Congress and signed into law by President Grant on March 1, 1872. The park is located primarily in the U.S. state of Wyoming, though it also extends into Montana and Idaho and was the first national park in the world. It is known for its wildlife and its many geothermal features, especially the Old Faithful Geyser. (Photo by Mark Ralston/AFP Photo)

World War II veteran Jack W. Schlegel, 91 years-old, from Mount Tremper, New York, of the 508th Parachute Infantry Division of the 82nd Airborne who parachuted near Sainte-Mere-Eglise on June 6,1944, poses with American and French flags as he visits the American War cemetery in Colleville-sur-Mer, on the Normandy coast June 2, 2014. REUTERS/Pascal Rossignol

Visitors enjoy watching the Blue Nemophila flowers bloom during the Golden Week holidays, at Hitachinaka Kaihin Park on May 02, 2010 in Hitachinaka, Ibaraki, Japan. Millions of nemophilas blossom across the “Miharashi No Oka” hill at Hitachi Seaside Park for the annual “Nemophila Harmony” flower festival. (Photo by Koichi Kamoshida/Getty Images)

Bangladesh is one of the few Muslim countries in the world where prostitution is legal. The Kandapara brothel in the district of Tangail is the oldest and second-largest in the country – it has existed for some 200 years. Here: Kajol with a customer. (Photo by Sandra Hoyn)

Russian soldiers rehearse ahead of a forthcoming parade on Red Square in Moscow on November 5, 2017 The event will take place on November 7, marking the 76 th anniversary of a 1941 parade, when Red Army soldiers marched past the Kremlin walls towards the front line to fight Nazi Germany troops during World War Two. (Photo by Mladen Antonov/AFP Photo)