On the south side of Lago Bayano, the Bayano Caves are a fun adventure. Cavers wade up Río Tigre though a sculpted Paleolithic cavern that is 850m long and full of bats and amphibians. Depending on water levels, it might be necessary to swim. Exploring the cave requires round-trip boat transportation, a guide, headlamps and helmets. Contact Igua's Tours in Panama City or local operators Bayano Tour or Panama Caves for the full package.