Just north of Crandon Park is a network of short and sweet seaside trails hidden from the whizzing lanes of traffic that connect Key Biscayne to the mainland. The Osprey Beach Trail meanders for a little more than a mile along the sandy dunes. The SPF-conscious will appreciate Bear Cut Nature Trail, which offers ample shade under the dense sea grape and mangrove trees. (Just watch out for mosquitos in the summer.) Don't miss the Fossil Reef Bike Trail, which leads down a boardwalk to reveal a fossilized mangrove reef forest and a postcard-worthy image of the Miami skyline.