Surf: The unreliable rivermouth left at Barra de Guaratiba can be Rio's best wave when the cylindrical walls spin down the triangulated sandbar. Fast, throaty barrels reminiscent of world-class spots on its day, but the crowds, localism and pollution detract heavily. The 40km beach to the west is military land and soldiers will chase, arrest and harass anyone walking on the beach, but paddling or SUPing is ok. Environment: Sharks regularly spotted near the rivermouth which brings more than just fish to the line-up.