Biscayne

Biscayne is roughly 95 percent water, and it shows: aside from a short boardwalk and mangrove trail near the visitor center, nearly everything worth seeing in this park is reachable only by boat. Beneath the surface lies part of the Florida Reef, the third-largest coral reef tract on Earth and the largest in North America, along with more than 40 documented shipwrecks scattered across the bay from four centuries of maritime traffic.

Boca Chita Key, a small island with an ornamental 1930s lighthouse built by a wealthy Standard Oil executive, is the park's most-visited destination for boaters and tour groups, offering a short loop trail and a lighthouse climb when it's open. Elliott Key, the park's largest island and the northernmost of the true Florida Keys, protects a rare stretch of tropical hardwood hammock forest.

Come for the reef and the history beneath the water. Stay for how different this park feels from any land-based national park you've visited. Read the story, book a boat tour if you don't have your own, and when you leave, collect the stamp.