White water rafting is one of the fastest growing outdoor activities in the world. 1. The rubber river raft was invented in the 1840s by U.S. soldiers. Lt. John Fremont wanted to survey the Rocky Mountains and the Great Plains so he enlisted the help of inventor Horace H. Day. Together, they constructed a primitive raft out of of four rubber cloth tubes and a wraparound floor. This raft made its first voyage when Fremont traveled the Platte River in 1842. 2. The International Scale of River Difficulty is used to rank rapids around the world. This scale includes Class I (Easy), Class II (Medium), Class III (Difficult), Class IV (Very Difficult), Class V (Extremely Difficult) and Class VI (Unraftable). The chances of surviving Class VI rapids are slim. 3. Modern rafting equipment has made the impossible possible. Once, the rafting on Tara River would obliterate expeditions, leaving boats in smithereens. Today, hundreds of tourists safety raft down the river each year. 4. John D. Rockefeller, Jr. built a resort with the nation’s first commercial rafting trips. In 1956, war surplus rafts were used by guests at Rockefeller’s resort at the Grand Teton National Park. Nevertheless, rafting didn’t really catch on until the 1960s and 1970s.