Steel was in short supply during the height of World War II, and there was nothing to be done but invent a replacement. One proposal was called Pykrete, a mixture of ice and sawdust that melted incredibly slowly. The idea faded away once the war ended—but now, a group of Finnish architects and engineers are reviving it. In a big, big way.
via Gizmodo
A Bizarre WWII-Era Supermaterial Made of Ice Is Making a Comeback