Jacques Cousteau once predicted a great struggle between those who defend nature and those who destroy it—with the Amazon as the eye of the storm. His dire forecast inspired the creation of Ariau Amazon Towers, an unconventional canopy retreat with 263 rooms, five miles of catwalks snaking along Rio Negro National Park, and a single mission: showcase what’s at stake in order to protect it ($200; ariautowers.com). Stationed deep within the world’s greatest concentration of biodiversity, Ariau guests might see a rare pink dolphin swim by one day and a white uakari dangling from a tree the next. Daytime activities include jungle survival courses with indigenous guides and exploring Anavilhanas, one of the largest freshwater archipelagoes on Earth. The big picture quickly becomes clear: This is one place we can’t stand to lose.