San Juan was an extremely important port for the Spanish, and the level of fortification there shows it. The fortress was attacked several times by the English during Spanish occupation, and was only taken once in a land invasion by George Clifford in 1598, who later abandoned it after all his troops got sick (I can't imagine why, the humidity was 70%+ every day I was there and it was crazy hot). The place was very impressive, and if you ever get a chance to go to Puerto Rico, I would highly recommend it. Unfortunately, the only camera I had was my cell phone, which took decent pictures, so I'm sure you could find better ones online somewhere, but if you want to check them out, here's the link. There are a couple of other random pictures in there of where I stayed and the plant I was at, just ignore those.
Link to Flickr
