Denver lies at the foot of the Front Range: the dramatic eastern face of the Rocky Mountains, where the Great Plains end and the Rockies begin.
Running 500km from southern Wyoming to southern Colorado, the Front Range contains some of the oldest and most spectacular peaks in the Rocky Mountains.
The range forms the eastern edge of the Rockies, rising dramatically from the flat plains that cover a large portion of the central United States.
Most of the range is comprised of volcanic rocks, in particular granite, which was created around a billion years ago at the time the North American continent was forming.
Approximately 300 million years ago tectonic forces began to uplift the granite, creating a large mountainous region known as the Ancestral Rocky Mountains.
As the granite continued to uplift over millions of years, it became covered with layers of sedimentary rock formed of sand, minerals and organic material deposited by wind and water.
As the mountains continued to be forced upwards, glaciers grew and slowly carved through the softer layers of sedimentary rock leaving behind huge peaks of ancient granite resulting in some of the highest mountains in the Rockies.
In fact, the Front Range is home to four of the 20 highest peaks in Colorado; at 4,352m Grays Peak is the highest mountain in the Front Range, located only 65 kilometres west of Denver.
Pikes Peak is one of the most well-known peaks in the range, and happens to be situated exactly on the continental divide: the point which separates the watersheds of North America’s rivers, dictating whether they drain into the Pacific or the Atlantic.
If a raindrop falls even slightly to the west of the continental divide it will flow into the Pacific Ocean, but if it falls to the east it will be redirected to the Atlantic.