Most people might think of steel, concrete, and glass when they think of a quintessential skyscraper. But Mjøsa Tower, designed by Voll Arkitekter, defies that image: Its 18 stories are entirely wood. The Norwegian marvel, which holds luxury condos and sweeping offices, is made of laminated timber, a material of thin sheets of glued-together lumber. The construction adds fire resistance, and unlike steel, retains its structural integrity in blazes. Its renewable material also allows high-rise owners to slash their carbon footprint, and the lack of concrete reduces dependence on sand, a surprisingly limited resource.