This is from the Participant Guide:
The Register's Annual Great Bicycle Ride Across Iowa,
RAGBRAI", is an annual seven-day bicycle tour across the state.
RAGBRAI is the oldest, largest and longest multi-day bicycle tour in the country.
According to participants, the event is the standard by which all other
multi-day bicycle tours are measured.
RAGBRAI started in 1973 as a six-day ride across the state by two Des Moines Register columnists who throught they were
inviting just a few friends along. About 120 people made it across the state that year. The next year, 2000 showed up. The number grew to 10,000 in 1985.
The ride annually attracts participants from every state and many foreign Countries.
RAGBRAI is coordinated by The Des Moines Register and is held the last full week of July.
The ride always begins on the western border of Iowa and always ends on the eastern border.
At this time of year, the prevailing winds are most often from west to east. Also, the riders are not facing the sun
at the end of a long weary day. Over the years, a tradition has developed for riders to dip their rear tire in the Missouri River
or its tributaries as they begin their seven-day jouirney east. When they complete the ride, they
will dip their front tire in the Mississippi River.