The town of South Park is a fictional place... But the valley it exists in is very real. Park County, Colorado, is a surreal valley 10,000 feet above sea level. It looks like somebody just dropped a massive section of the US midwest into the mountains, with snow-capped peaks on all sides.
The Colorado River is birthed in the Rocky Mountains. Here, it is little more than a stream through a swampy wetland full of mosquitoes.
