The desert of Nevada reveals to Matt what's essential for survival — for him and for his horse, Smokey. The blazing sun and isolation peel away at Matt and threaten his morale for the long journey ahead.

Matt makes his way into the Sierra Nevada mountain range, and encounters the first true test of his ability to withstand the wilderness alone. He learns about equipment he doesn't need - a tent - and which he does need - a staple gun.

In order to ride horseback across the country, Matt would need a horse and a trail. The problem is there were no modern trails that were tested all the way across on horseback. And there were few modern examples of what kind of horse would be good for a 5,000-mile ride.

Twenty years ago, Matt Parker was in that weird phase of life right out of college; rudderless and adrift, unsure of what adulthood would hold. And then an idea hit him like lightning — he'd ride across the country on horseback. Never mind that he'd never really spent time with horses. But he was ready for the challenge of a lifetime.

In 2003, Matt Parker set out on a journey that would take years to complete. He became the first to ride horseback across the country on the American Discovery Trail.