and welcome to what may be the mode of transport of the future.
The possible mode of transport of the future is the amphibious, single wheeled, pedal powdered, submarine.
And below is a 3d model of it made in 123d design desktop, available to download here- http://www.123dapp.com/design
Now if you want to know how i made read on ( and i recommend this) but if you just want the 3d model here it is - http://projects.123dapp.com/smb-123D_Design/monowheel-submarine/1783645
And don't forget to vote for the monowheel submarine in the 123d design contest if you think it should win.