Penny-farthing

Penny-farthings were an early form of bicycle.

While strapped into the Morok mind-reader, the First Doctor was questioned by Lobos on how he came to Xeros. He thought of a penny-farthing and an image of one appeared on the device's screen. (TV: The Space Museum)

The Eleventh Doctor stated that he once saw a tandem penny-farthing. (COMIC: The Sound of Our Voices)