Guarding the north side of the harbor opening, El Morro is a defining feature of the Havana skyline. It too was built in the 16th Century. The British decided to bypass this choke point in the Seven Years War; they landed a force to the east and took the fort from behind. After they gave it back, Spain constructed Havana’s forth-and largest fort-La Cabana. I took a ferry across the harbor to visit it.