Tourists walk over sand strewn with Sargassum algae at Gaviota Azul beach in Cancun July 17, 2015. Ninety tons of Sargassum, which releases a pungent smell as it decomposes, has been cleared by authorities. According to some biologists, ocean currents have brought the algae from the Sargasso Sea in the Atlantic Ocean to the coasts of Quintana Roo, local media reported. Gaviota Azul beach is one of the most visited beaches in Cancun. REUTERS/Victor Ruiz Garcia