Nature by name and nature by, er, nature, this stunning eco lodge sits in the heart of Bald Eagle State Park in Pennsylvania, overlooking a tranquil 1,700-acre lake. The hotel has just 16 rooms in total but each is an oasis of calm, offering lakefront views, sweeping balconies and natural-wood furnishings. It’s heated and cooled by geothermal technology, while a rainwater recycling system is used to flush toilets and recycled metal, glass and wood are used throughout. These adaptations, along with other energy-saving measures, have allowed it to achieve a 30% water use reduction and a 14% decrease in energy costs.