Gulf Islands National Seashore

The highlight of the Florida Panhandle, this 150-mile stretch of mostly undeveloped white-sand beach is a prime example of what the Gulf Coast looked like before human settlement (which, to be fair, can often be seen in the form of high-rises in the distance). The National Seashore is not contiguous, but you'll find portions all along the coast: long swaths of sugar-white dunes crowned with sea oats, a perfect example of pristine flatland beach.