The tallest (and pretty much only) structure on the island of Navassa.  In 1856, the United States Congress passed an interesting bill called the Guano Islands Act, which President Pierce didn’t have to think twice about signing into law.  The Guano Islands Act simply said that any citizen of the United States was permitted to claim any island they discovered as an American possession, provided that island had significant deposits of guano (aka bird poop) on it.  Any such islands, of course, could not be already possessed by another country.  The islands didn’t have to be very big, or even be islands at all.  It also applied to barren, uninhabitable rocks that might poke over the surface of the sea.  Now, the United States, like a number of other countries, was going through an expansionist period in the 19th century, but why would it care about small, remote islands like these?  They’re too small to colonize and too remote to be of strategic imp...