My friend took me to see the Cabo de Rama fortress, which was claimed and then abandoned by the Portuguese. The walls and cannons are still there, but the jungle has taken over, and banyan trees offer a fragile protection to modern visitors.
I didn't get a good picture of this, so you'll have to take my word for it, but deep in the jungle heart of the fortress, a wide flight of stone stairs descend into a sunken layer, overgrown and claimed by vines. Dappled shade hides these stairs from all but the most observant of guests, and there's something eerie about them, as though they were the last ascent of those doomed to a beheading.
After the fort, we went to visit a secret beach a few kilometers away. My friend explained that leopards descend into the valley after dark and snatch up stray dogs. When we visited, everything was peaceful - everything, that is, except for a group of Russians doing coke off each other's stomachs.