Project Habakkuk: During WW2 the British prototyped an aircraft carrier made of ice at Patricia Lake in Jasper

Pretty crazy what lengths militaries will go to win a war!

"Project Habakkuk or Habbakuk was a plan by the British during the Second World War to construct an aircraft carrier out of pykrete (a mixture of wood pulp and ice) for use against German U-boats in the mid-Atlantic, which were beyond the flight range of land-based planes at that time."