Built in the mid 1600s and expanded a couple of times, this fort became Spain's largest in any of her colonies. It's humungous and entirely takes up the top of a 130' hill with a perfect location to protect the rich port from marauders by land or by sea. 

Cartagena was South America's first port. Imagine it. All the wealth from Peru's silver, Colombia's emeralds, and rich plantations everywhere -- it all had to come through Cartagena. This was every pirate's dream but Cartagena stood proud, beating back all but one -- the sly, determined French pirate Baron de Pointis who, in 1697, attached from the rear were they were not well defended. 

It even held firm against an attack by the combined forces of the British Admiral Vernon and the 13 colonies who brought 25,000 men and 186 ships. Held off by 3,000 spanish troops and 6 ships the British and her colonies slunk back home after a disgustingly unsuccessful month long siege. 
 
The walk up the ramparts was made a bit unpleasant by the intense equatorial sun, but whenever we could find a spot of shade we paused to listen to the English translation on our headphones and were able to learn quite a lot of the fort's history. It's definately worth seeing. We came in the morning but not early enough it seems, as I thought I'd have heat stroke before we finally got back down and found a cool place to recover.