And yes, that's in one day, without a car. Ultra-marathoner John Wagner runs 100 miles in 24 hours. You can do more than you think you can. The Grand Slam consists of three main races in California, Colorado and Utah.
Runners can choose their fourth race, either in Virginia or Vermont.
Eleven athletes completed the Grand Slam in 1999. Each course boasts its unique hazard. The California race starts at the foot of a ski hill and continues through deep canyons with stagnant hot air. The Colorado race takes runners 10,142 feet above sea level, making breathing a challenge even when you're not running. To add to the adventure, sometimes there are only three weeks to recover between the Grand Slam races.