You can easily spend a full day sightseeing at these downtown Denver attractions. After dark, horse-drawn carriages clatter up and down the mall. This area is home to some of the most popular places to visit in Denver, like Denver Union Station and the LoDo Historic District. Pei designed the gray and pink granite pathway to resemble the pattern of a diamondback rattlesnake. But you can save on shoe leather by riding the free shuttle bus on the 16th Street Mall – it makes everything in downtown easy to reach and stops at every corner. Denver has one of the most walkable downtowns in the nation.