Task: Question Generation
Input (English): In addition to the sports he played at Yale, Kerry is described by Sports Illustrated, among others, as an "avid cyclist", primarily riding on a road bike. Prior to his presidential bid, Kerry was known to have participated in several long-distance rides (centuries). Even during his many campaigns, he was reported to have visited bicycle stores in both his home state and elsewhere. His staff requested recumbent stationary bikes for his hotel rooms. He has also been a snowboarder, windsurfer, and sailor.
Output (English): What are 'centuries' in bicycling?