Ariau Amazon Towers Hotel, Brazil
The one essential building block for a large tree house is a big, sturdy tree to support it. So it stands to reason that Brazil, which is home to the world's largest rainforest, would be a pretty good place to build a tree house. And that's exactly where you'll find the Ariau Amazon Towers Hotel -- specifically at the confluence of the Rio Negro and Ariau Creek. It's a large rainforest retreat that consists of eight wooden towers with 268 treetop rooms that have views of the surrounding treetops. But it's the tree houses that we're interested in. In addition to the main towers, Ariau features several rustic tree houses that are suspended in the trees above the flowing river. The tallest tree house is the Tarzan House, which is located about 72 feet (21.95 meters) above the ground in a mahogany tree and has its own its own private balcony and hot tub [source: Travel + Leisure].