The tiny earthbag dome at the Permaforest Trust, Australia.

This is the earthbag dome at the Permaforest Trust near Brisbane, Australia. A naturally built dome's roof is especially difficult to protect from rain. This design uses a clever system of hand sculpted fins that channel the rain away from the walls into drain pipes. It's a technique similar to the fins used to protect walls in Asir architecture, Saudi Arabia.

You can see more design details read about building with earthbags here.