Everyone has heard of the Tour de France, one of the world's premier extreme road races (approximately 2,000 miles over the course of 21 days). Although the riders are only in the saddle for 4-6 hours per day, the speeds they carry are incomprehensible to most cyclists - nearly 30 mph on flats (consistently); nearly 15 mph on very steep climbs; sometimes 60+ mph on Alpine descents; and an unbelievable 40-45 mph in the sprints!There are other races, though - in particular, the Race Across America, which is arguably the most difficult road race in the world. Racers ride from the west coast to the east coast of the USA, following a prescribed, closely monitored route. Racers can do the race as solo competitors, as a two-person, a four-person or an eight-person team. The 8-person teams are generally "fun" teams, and usually ride for the benefit of a charity.The solo racers cross the continent in 10-12 days of long, long days in the saddle (20-22 hours per day). Duo teams takes approximately 7-9 days to finish. In duo, the racers alternate riding and resting; each rider is in the saddle 12 hours every day. The four-person is by far the fastest, crossing the country in about 5 days. This category is all about speed. Each rider takes short turns of approximately one hour (with a 3-hour rest); and their shift is ridden time-trial style which is much, much faster than the endurance pace held by the solo or duo riders.Considering that the USA is approximately 3,000 miles wide, the Race Across America is an incredible accomplishment, no matter the category a rider participates in!