What to expect: Built by Florida developer Henry Flagler on Key West's south shore in 1920, Casa Marina Resort - Waldorf Astoria Collection is marked by tropical gardens and sculpted hedges. The main building has a sand-colored exterior with a Mediterranean red-tile roof, and newer buildings echo the grand resort style. Arrayed along a 1,100-foot private beach, the resort is 1.5 miles from the shopping, dining, and nightclubs of Duval Street.