The original Zeppelins were based on a rigid design in which separate gas-tight compartments were surrounded by a metal frame covered with a non-airtight fabric.

ECONOMIST: Pushing the envelope

Instead, Huibers and his team built the boat by welding together the metal hulls of 25 barges into a single frame, which was then covered with Scandinavian pine.

CNN: Dutchman builds replica Noah's Ark after flood dream

The tear-shaped frame of the Treetent is constructed from steel, covered in canvas and anchored to a tree trunk.

CNN: Sculptor creates treehouse-like tent

The design featured a wooden frame on top of a concrete-slab foundation, with an exterior covered in gray asbestos shingles. (Steel was in short supply.) The structure violated the Cambridge fire code, but it was granted an exemption because of its temporary status.

NEWYORKER: Groupthink