But not every trail dares you to tackle steep elevation changes with hill sprints.

Link up with paths leading to the Boulder Reservoir for higher mileage and more views of the Flatirons.

The U.S. Forest Service divides the trail into four manageable sections, each accessible by car.

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Here you’ll find Black Balsam Knob, a treeless mountaintop with vistas of thick forests and grassy knolls.

Ample connector trails enable loops of any distance.

The pale granite of Sierra peaks against azure sky looks like a postcard snapshot.

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(If you’re going more than 6 miles, get a day permit atKalalauTrail.com.)

Poison Spider Mesa offers a particularly scenic 13-mile loop on a rim overlooking Moab and the La Sal Mountains.

Take in the views of downtown Portland and Mount Hood, then run back downthe perfect 5-mile escape.

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The hilly terrain lures Chicagoanswho call the area “Palos"seeking an alternative to their pancake-flat waterfront path.

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