The Galapagos Islands are for passionate adventurers, where you can swim with friendly sea lions who come up to peer into your mask. You'll also see swimming iguanas. The Ecuadorian government tightly controls the trips, so there are never too many people on each island. Be sure to visit the Darwin Research Station on Santa Cruz to see Lonesome George, an 80-year-old giant tortoise who is, sadly, the last of his breed. A volcano erupted during our visit, and watching molten lava pour into a steaming sea was like the beginning of time, but so are the Galapagos.