The Ford GPA 'Seep' was an amphibious version of the WWII Ford GPW Jeep. The 'Seep' however, did not enjoy the success of its land-based brother. It was slow, heavy, cumbersome, and was deemed unfit for amphibious operations.
1954 Willys Jeep promotional film - video
Competitive Jeep speed disassembly - GIF and video
autobiography of a Jeep
Jeep CJ-5 Go-For-Digger
Steam-powered Jeep JK 6-wheeler - photos and video
Jeep drives down a steep ravine - GIF