Northerly neighbor Miami has no shortage of pools — but none like the Venetian Pool. Opened in 1924 as the Venetian Casino, this unique, 820,000-gallon public swimming hole is set in an old quarry pit and fed with spring water from an underground aquifer. The pool itself is surrounded by two Mediterranean-style lookout towers, two waterfalls, and several cave-like grottos, all of which help earned it a listing in the National Register of Historic Places — the only swimming pool to earn the designation. Of course, all this luxury comes with a (modest) cost, but for the blast of tranquil refreshment it provides on a hot summer day, it's well worth the price.