About 68 miles west of Key West, Florida, in the Gulf of Mexico lie seven islands that make up Dry Tortugas National Park. It is unusual in that 99% of its area is made up of water that make it ideal for snorkeling, scuba diving, swimming, fishing and kayaking. The other unusual fact is that it is home of a massive, unfinished fort, Fort Jefferson. The fort is huge, being the largest masonry structure in America, comprised of over 16 million bricks. Construction began in 1846 and was thought to become a fort that would aid in suppressing piracy in the Caribbean. It was used during the Civil War as a holding place for Union soldiers that had committed mutinous acts. The fort ultimately was never finished due to fears that the island might not be able to support the weight that finishing the fort would require. Walking around this huge fort is certainly a trip back in history. Every crook and cranny has something of interest. Each casement window, like this one, has a different look to discover.