Today's $100,000 U.S. Pro Cycling championship in Baltimore's Inner Harbor--the richest one-day purse in bicycle racing history--has attracted 75 of the world's top riders to a 62.5-mile circular course that some contend is among the most difficult for riders and the best for spectators.

If 75 of the world's best riders competing for a $100,000 purse sounds familiar, it should.

The three-day, 284-mile Tour of America bike race had both when it finished here in April during the Cherry Blossom Festival.

But few riders are the same, since multiple-day road races are as different from "criterium" racing around Baltimore's six-mile city course--with cobblestones, sharp corners, hills and a tunnel--as the marathon is from the 100-yard dash.

Among the dozen who will ride both races are Jonathan Boyer, the only American to race in the Tour de France and the top U.S. finisher in the Tour of America (24th); John Eustice, the top American finisher last year in the first U.S. Pro race in Baltimore, and Canadian Ron Hayman, who won the final leg of the Tour of America.

Among the favorites are Belgium's Eric Vanderaerden, Denmark's Hans Hartik Oersted and Gert Frank, and France's Marc Gomez, Gilbert Duclos and Francis Castaing, who won the first leg of the tour of America.

The six-mile Inner Harbor course not only offers spectators free, close-up grandstand views of the race but also a chance to ride their own bicycles on the course, between 10 a.m. and noon.