If you described the concept of a roller coaster to an alien, they'd probably be baffled: Why on Earth are humans purposely recreated the sensation of falling, flying and -- quite possibly -- feeling close to death? In the first part of this special two-part series, the guys explore the origin story of modern roller coasters, from the old days of "Russian Mountains" to an amusement arms race that continues today: the ongoing quest to build the biggest, highest, fastest rides on the planet.