SS Autoliner may some day cross oceans, according to Karle Moench of Berlin, Germany in 1950. This was a small version of a sea-going car which operated on the road, or in the water with equal efficiency. Note the fin-like tail on the amphibious vehicle.
Looks like Park La Brea, L.A. in the background when it was being built in 1944. I don't have a nice story to go with it like jnaki would. There's plenty of interesting info out there about it if someone's interested.