Xtreme Divers also offers Eco Tours. The Window Cave/Tanamá River. This is a swim & hike through the water carved canyons of the Tanamá River. Explore caves, see bats and unmatched scenery from a height of hundreds of feet, all from Window Cave.See the impressive Arecibo Observatory, the world's largest radio telescope/antenna. Requirements: Large "ziplock" type plastic bags. A complete change of clothes (including shoes and towel) Snacks sealed in waterproof bags and liquids in PLASTIC containers, in a small backpack . Physical Condition - Good physical condition is required. Recommendations-Clothing of fabrics that do not absorb much water and light boots. Sleep well the night before. Eat a hearty breakfast and be on time.Optional items: gloves, shin pads and wet suit. Smoking Only in designated areas (away from our natural surroundings).