The Hornet's Nest
Literally. I don't know how I made it down there, but this French couple we met down the hill said it was worth going in this direction and that "if not afraid of bees," I should go see this underground fountain. There must have been 100 bees in this pit swarming around. Not about fear, more like being suicidal.
In Greek Mythology this is the fountain of Pirene from which Pegasus would drink.