Much of the cave art in Puerto Rico was made before the Spanish arrived in 1493 and includes detailed portrayals of humans and animals, like this stingray. (Image credit: A. Acosta-Colón) Ancient ...

The island would fit tidily inside Connecticut. With a population of 2,300,000, Puerto Rico is as crowded as the U.S. would be if all the people in the world were packed into it.