As the capital of Colorado State, Denver is located with a backdrop of the Rocky Mountains which are just to the east. The Rocky Mountain Arsenal is a natural wildlife refuge which plays home to bison, wild birds, deer and prairie dogs, amongst other wildlife. Car hire from Denver will allow you to head out to the reserve where you can experience guided tours of the area but reservations are required. Being the capital city, the Colorado State Capitol building is a must visit if youre in the area from the top of the building you can see panoramic views of the mountain peaks. If youre hiring a car in Denver, then you can head straight out to the mountains, its just under a three hour drive.