Indoor Pool, Hotel Alcazar, St. Augustine, Florida (circa 1888-1897 and 2015)
In the Hotel Alcazar in St. Augustine, Florida (built 1888), this was said to be the largest indoor swimming pool at the time and even hosted national swimming events. Now it's part of the Lightner Museum Antique Mall and the Cafe Alzacar. Depths of the pool ranged from 3 to 12 feet.
