This huge tricycle built by Kanyaboyina Sudhaker of Hyderabad takes 300 pedal revolutions for each wheel revolution. The wheels on this 42 foot tricycle has wheels that are 17 feet across. This trike is in the Guinness Book of World Records as the world's largest tricycle. Thank you to Roto1000 for this tip.
More about Sudhaker and his vehicular creations are at his website.