Is it a car? Is it a boat? The Amphicar was both.
Produced in Germany from 1961 to 1967, the Amphicar could transition from driving on land to cruising through the water with twin propellers pushing it along at a leisurely seven knots. Its front tires act as rudders, steering the car/boat.
Nearly 4,000 Amphicars were produced, making it the most popular non-military amphibious vehicle ever sold. The Amphicar never took off due to a high price tag, mediocre on-road performance, and not-so-great performance on the water.
Famous Amphicar owners include President Lyndon B. Johnson.