The North Side Skull & Bone Gang stand together during the wake up call for Mardi Gras, Tuesday, February 9, 2016, in New Orleans. Their costumes are intended to represent the dead and they bring a serious message, reminding people of their mortality and the need to live a productive and good life. (Photo by Brynn Anderson/AP Photo)

Party-goers partake in a festival better known as Holi One, during International Workers Day in Johannesburg, South Africa, 01 May 2015. The colour festival promotes togetherness as well as colourness in everday life. May Day is observed worldwide every year on 01 May. (Photo by Kevin Sutherland/EPA)

Former Soviet leader Mikhail Gorbachev attends the Gorby 80 Gala at the Royal Albert Hall on March 30, 2011 in London, England. The concert is to celebrate the 80th birthday of the former Soviet leader Mikhail Gorbachev.

Those lights are actually bioluminescent shrimp, better known as sea fireflies, or, in Japan, as “umibotaru”. Visible every year from May until the end of October, they live in the sand around very shallow sea water and are often seen floating between the extremes of high and low tides. Here: Bioluminescent sea fireflies glittering like diamonds on the rocks and sand. Okayama, Japan. July 2016. (Photo by Trevor Williams/Jonathan Galione/Getty Images)

People visit the autonomous urban concept car Renault EZ-GO during the first press day of the Geneva International Motor Show on March 6, 2018 in Geneva. The show opens to the public on March 8 and runs through March 18. (Photo by Fabrice Coffrini/AFP Photo)

People watch as an acrobat rides his motorcycle around a circular track at an entertainment park set up outside a shrine in Rawalpindi, Pakistan, on June 19, 2013. (Photo by Muhammed Muheisen/Associated Press)

Actor Bruce Willis and wife Emma Heming arrive at the premiere of the HBO documentary 'His Way' at Paramount Studios on March 22, 2011 in Hollywood, California.

Members of the “Avalon” team wearing 14th century knight costumes fight against each other on the bank of the Yenisei River during the regional amateurs tournament of clubs of historical reconstruction, “The Battle of the Nations 2015. Siberia”, in Krasnoyarsk January 24, 2015. (Photo by Ilya Naymushin/Reuters)