Presidents are well-known for their getaway locations, whether they choose to clear brush on a ranch in Texas, visit their childhood home in Hawaii or retreat to nearby Camp David. Less common in the modern era is the practice of building and maintaining one's own official home-away-from-home that also acts as an office-away-from-office, but that was more common in Truman's time, and he took full advantage.
Thus the creation of what was known then as the "Little White House", a compound obtained and maintained by the Truman administration in the balmy tropical paradise of Key West, Florida. Truman made his love for Key West no secret, as not only did he set up an official secondary location for conducting state business on the island, he also annexed several miles of its sandy southern shoreline and created a naval base there, which is maintained to this day.
The building is now the Harry S. Truman Little White House museum. Complete with many of the original fixtures, amenities and objects of historic interest, the museum is a snapshot of a time when the presidency came with at least a bit more privacy, and keeping a sharp eye on Cuba came at a premium.
Truman's favor for the island did make sense. Key West has long been a location of strategic importance, whether it was an early warning location guarding against potential attacks by the Spanish navy, or a valuable outpost during the civil war. Bases such as Fort Zachary Taylor and Fort Jefferson in the Dry Tortugas - both historic parks now - were built there more than a century ago. With Cuba just 90 miles away, it took on a whole new importance during the Cold War, one that Truman didn't shy away from embracing. Particularly, one would think, after he saw that Caribbean water.