Set out on the tiny islet of Naos near the very end of the Amador Causeway, this part of the Smithsonian's Tropical Research Institute is an open-air museum dedicated to the interpretation and conservation of the coast. Kid-friendly, there's a "touching pool" where kids can get up close and personal with sea cucumbers and starfish, as well as turtle and shark pools. There are also white mangroves, tropical aquariums with native species, and a nature trail that winds through the dry forest. Strategically set on the site of a former U.S. defense base, the site has sweeping views of the entrance to the canal. The opening of the Bio Museum nearby has caused attendance to fall, therefore you'll likely have this place all to yourself. Bring sunscreen as you'll be outside quite a bit. You'll need a few hours here. Note that the Nature Center is closed from April through late December.