To get his railroad built across the islands, Henry Flagler had to quarry out some sizable chunks of the Keys. The best evidence of those efforts can be found at this former quarry-turned-state park. Windley has leftover quarry machinery scattered along an 8ft former quarry wall, with fossilized evidence of brain and staghorn coral embedded right in the rock. The wall offers a cool (and rare) public peek into the stratum of coral that forms the substrate of the Keys.
There are also various short trails through tropical hardwood hammock that make for a pleasant glimpse into the Keys' wilder side. Borrow a free trail guide from the visitor center. From December to April, ranger-led tours are offered at 10am and 2pm Friday to Sunday for $2 per person.