Jacobs, Herbert and Katherine, Second House National Register of Historic Places Listing

The Jacobses needed more space. They had already lived in Frank Lloyd Wright's first Usonian masterpiece, but three growing kids meant they were bursting at the seams. So, they hired him again. Wright built them a massive curve of Laurentian sandstone and glass. To block biting Wisconsin winds, he piled a giant dirt berm against the north wall, burying it up to the eaves. It worked. During freezing winters, the building kept itself warm. He positioned the glass southern facade to catch the low winter sun, while a sunken circular garden out front bounced extra light inside.

Building it was tough. Herbert Jacobs actually did much of the physical labor himself to keep costs down, hauling stone and mixing concrete. Inside, Wright suspended the bedroom balcony from the roof rafters using thin steel rods. No support pillars blocked the view. This design didn't just look cool it was a prototype. Decades before the 1970s energy crisis turned "green building" into a buzzword, this house was already utilizing the earth's natural thermal mass. The floor slab absorbed heat during the day and radiated it at night. It paved the way. Today, it stands as the grandmother of modern sustainable architecture.