Tourists play at a beach covered by a thick layer of green algae on July 3, 2013 in Qingdao, China. A large quantity of non-poisonous green seaweed, enteromorpha prolifera, hit the Qingdao coast in recent days. More than 20,000 tons of such seaweed has been removed from the city's beaches. (Photo by China Foto Press)

A ten days old South American sea lion pup sits next to its mother Lunita at the “Tiergarten Schoenbrunn” Zoo in Vienna, Austria, July 28, 2015. The pup was born in the zoo and weighs about 14 kilograms (30 pounds). (Photo by Leonhard Foeger/Reuters)

People try to board a goverment bus during the second day of a suspension of public transport services in Apopa, El Salvador July 28, 2015. Violent gangs in El Salvador ordered bus drivers to strike on Monday in a conflict that has killed six people and left thousands of commuters stranded on the streets of the Central American capital, police and bus company officials said. (Photo by Jose Cabezas/Reuters)

People perform during celebrations to commemorate the 70th anniversary of the establishment of the Vietnam Public Security police force at the National Convention Center in Hanoi August 18, 2015. The Vietnam Police force was founded on August 19, 1945, the day of the anti-colonial people's uprising known as the August Revolution. (Photo by Reuters/Kham)

Desiree Urban is painted at Columbus Circle as body-painting artists gathered to decorate nude models as part of an event featuring artist Andy Golub, Saturday, July 26, 2014, in New York. Golub says New York was the only city in the country that would allow his inaugural Bodypainting Day. (Photo by John Minchillo/AP Photo)

Jason Ramsay and Amy Laverty, from Arbroth, Scotland, pose beside a large Christmas tree at Bondi Beach on December 25, 2016 in Sydney, Australia. Bondi Beach is a popular tourist destination on Christmas Day. (Photo by Don Arnold/Getty Images)

A Sadhu or a Hindu holy man performs to receive money from pilgrims at a makeshift shelter, before heading for an annual trip to Sagar Island for the one-day festival of “Makar Sankranti”, in Kolkata, India, January 10, 2018. (Photo by Rupak De Chowdhuri/Reuters)

Revellers celebrate “Ash Monday” by participating in a colourful “flour war”, a traditional festivity marking the end of the carnival season and the start of the 40-day Lent period until the Orthodox Easter, in Galaxidi, Greece February 19, 2018. (Photo by Alkis Konstantinidis/Reuters)