While you have to pay to access the nearby Chatfield State Park, Waterton Canyon offers a free alternative for anyone looking to break a sweat. The popular six-and-a-half mile dirt trail to Strontia Springs Dam was closed in early 2016 due to flooding the previous year, but repairs have been made, and it's back to being open everyday. Biking and hiking are the most common activities here, but the bonus is the riverside views and frequent sightings of bighorn sheep and mule deer along the way. And as the Denver endpoint of the 486 mile-long Colorado Trail, you could theoretically journey all the way to Durango... if some sort of weird, wild wanderlust overtakes you.
With Downtown views that can't be beat, this is urban exercising at its best. The 330-acre park is also home to the Denver Zoo and the Museum of Nature and Science, but you can visit those after you take a ride (or run, or walk) on the 3.1-mile trail that loops around the park and its two lakes. Or maybe after you hit up the baseball, football, or soccer fields. Or how about a game of tennis, or a yoga session in the shade under the trees? Just don’t be surprised if you also run into a festival, outdoor market, or wedding along the way since this is also a popular spot for summer events of all kinds.