The history of the Citroën 2CV is pretty remarkable. The French had completed the first prototype right before the Germans invaded. When they realized that the Germans were coming, not wanting the car to fall into German hands, they had the prototype disassembled, crated, and hidden in the sewers under Paris and the engineers took the plans with them when they fled the invasion. After the war, no one could remember where they hid the prototype, and efforts to find it failed. Then, in the 1980s, someone found the crates. They reassembled the car and it started on the first try.