History of Diving Museum – Four thousand years of diving history is captured in 13 interactive galleries. Highlights include a glimpse at some of the earliest scuba gear. Don’t miss the helium bar on your way out.
Theater of the Sea – With up-close encounters with dolphins, turtle feedings and sea lion shows make this marine-mammal center (the second-oldest in the world) a popular all-day destination for families. There’s also a grill, gift shop and private beach for swimming and sunning.
Lignumvitae Key Botanical State Park – This 280-acre island earned a place on the National Register of Historic Places, thanks to its virgin tropical hardwood forest and 1919 home of William Matheson, a well-to-do Miami chemist. Accessible only by boat, it’s open for tours Friday through Sunday.