4. Tree House: Morgan's Rock Hacienda & Ecolodge, San Juan del Sur, Nicaragua – Travelers' Choice Winner 2009: Best for Romance, Best Luxury – Average Nightly Rate: $257
It's all about trees at Morgan's Rock, which has planted one and a half million trees for farming to help reduce forest destruction, and added nearly 100,000 permanent new trees to the property to provide a home for wildlife. When the lodge was constructed, extra wood was used to build furniture in the rooms, and trees on the property are allowed to grow naturally, with some even growing through the cabin roofs. One TripAdvisor traveler says, "It's a totally unique experience, and it hits all of the right notes for friendliness, service, and comfort, with a conservation and community development focus."