At points along US Highway 1, the road itself is the only thing separating the silvery Atlantic from the blue Florida Bay. Driving south, the steady countdown of the green-and-white mile markers leaves you feeling that the road and the continent are both nearing their end. At marker 110 on historic Key Largo, you're just an hour out of Miami, but a world away. It's the diving capital of the world, some think, and as famous for sport fishing as Islamorada, just down the highway at marker 85. Past Marathon and the Seven Mile Bridge and across Big Pine Key the countdown continues: 30, 20, 10 miles to go before the end of the line at old Key West - the southernmost city in the Continental United States. On you trip down this chain of mangrove-fringed islands, you've passed reefs, jungles, and countless beautiful luxury homes, too. Finding one to call you own in scenic Key West might take a few more trips on the Overseas Highway, but that's half the fun.