In 1809, John Colter, a hunter, travelled to a new part of the United States: the mountains and forests of Wyoming. He discovered an amazing place. It was an extraordinary land of ice and fire. When he returned home, he talked about his adventures - but nobody believed him!
Colter described amazing scenes. There were ponds of water - but they boiled! There were trees that appeared to be stone. There were holes in the ground that suddenly exploded, like fountains of boiling water. Everywhere there was the strong smell of sulphur.
Colter walked deep into the forests. He watched and studied an amazing variety of animals, including bears and wolves. He climbed high mountains and explored beautiful lakes and rivers. There were high waterfalls and deep canyons with yellow rocks on each side. In fact, the name of this place comes from those rocks: Yellowstone.
Fifty years later, the US government organised three scientific expeditions to Yellowstone. They wanted to find out what was really there. Finally, people started to believe John Colter's stories. They realised Yellowstone was a beautiful and unusual place, and asked government to protect it. So in 1872, President Grant signed a new law: Yellowstone was now the first national park in the world.