Rio Perdido is this tucked-away little world in Guanacaste, Costa Rica, set on a 1,500-acre private reserve surrounded by raw, wild nature. It sits on a bluff between two river canyons—one with cool, clear water (Río Blanco) and one that’s naturally hot and mineral-rich (the “lost river,” Río Perdido), so you literally get both refreshing swims and steamy soaks in the same place