The Blue Man Group performs on stage during a media preview ahead of their show in Singapore on March 31, 2016. Blue Man Group was started by three friends in New York in 1991 as a way to celebrate the human spirit through music, science, art and theater. (Photo by Roslan Rahman/AFP Photo)

Young man making the O.K. sign. (Photo by George Marks/Retrofile/Getty Images). Circa 1950s

Pope Francis greets the crowd from his popemobile in downtown Rio de Janeiro. Pope Francis touched down in Rio de Janeiro on Monday, starting his first foreign trip as pontiff and a weeklong series of events expected to attract more than a million people to a gathering of young faithful in Brazil, home to the world's largest Roman Catholic population. (Photo by Ueslei Marcelino/Reuters)

Super-cell thunderstorms, whirling tornados and lightning bolts illuminating the sky – these photos capture the terrifying brilliance of American storms. (Photo by Brandon Goforth/Solent News & Photo Agency)

Burger King employee Rumi Sekine shows the Kuro Diamond burger, right, and the Kuro Pearl burger at its Shibuya restaurant in Tokyo Tuesday, September 16, 2014. The international hamburger chain in Japan will launch the two new “kuro burger”, or “black burger” menus that sport buns, cheese and sauce all in black color, starting on Friday, Sept. 19, for a limited period. The buns and cheese are darkened with bamboo charcoal while the beef patties made with black-pepper are topped with the garlic sauce using squid ink. (Photo by Koji Sasahara/AP Photo)

Ariel Winter attends the 4th Annual Just Jared Summer Bash on August 13, 2016 in Los Angeles, California. (Photo by JB Lacroix/Getty Images)

An American soldier walks ahead of an MKIV (Mark IV) British-made tank, circa 1918. (Photo by Hulton Archive/Getty Images)

Performance of the actress Asia Argento dedicated to the exhibition of the tattoo artist Marco Manzo at the Vittoriano museum in Rome, Italy on December 11, 2018. (Photo by Barbara Amendola/IPA Press)