Tourists play at a beach covered by a thick layer of green algae in Qingdao, China. A large quantity of non-poisonous green seaweed, enteromorpha prolifera, hit China's Qingdao coast last month. More than 20,000 tons of such seaweed has been removed from the city's beaches. This has now become an annual summer event. (Photographs © Whitehotpix/ZUMA Press)