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Baumraum makes prefabricated tree houses in its workshop, then trucks or ships the components to a site. Each structure is fastened to sturdy trees by cloth belts and steel cables without using bolts or nails. Built-in benches, electricity, heating and a kitchen are optional. Although the company's primary market is Europe, its first U.S. tree house will be a New York family's vacation home. Prices range between $28,000 to $71,000, plus delivery.

Credit: Alasdair Jardine/Baumraum

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