![A man on an amphibious cycle (capable of operation on both land and water) in Paris, 1932 [882×635] Credit: Nationaal Archief Check this blog!](https://64.media.tumblr.com/cfa8e8bffc74e4f3238637ee5d61e7c9/1c91b30fa49c5ea7-4f/s500x750/9965d4185814402781689ac9a6e9f93087e466be.jpg)
A man on an amphibious cycle (capable of operation on both land and water) in Paris, 1932 [882×635] Credit: Nationaal Archief
Amphibious bike
alternativebyfritz
A man on an amphibious cycle (capable of operation on both land and water) in Paris, 1932 [882×635] Credit: Nationaal Archief
alternativebyfritz 
Without some other means of forward-propulsion, I doubt if mere pedal-power would get you anywhere. Maybe the first water-enveloped exercise bike.