Bahia Honda State Park on Big Pine Key is one of the most beautiful spots in the Florida Keys, with white-sand beaches, clear turquoise water and a relaxed island feel. Its shoreline is among the best in the Keys for swimming and sunbathing. The park is also known for the old Henry Flagler railroad bridge at Bahia Honda Channel, a striking piece of early 1900s engineering that visitors can climb for wide views. Snorkeling, kayaking and camping make it easy to spend a full day or several days here. Entry is $2 to $6 per vehicle, camping runs $16 to $40 per night, and tours cost extra. Book campsites and cabins far in advance, since they are extremely popular.