A bear family takes a walk through a meadow near the Petrified Tree in northern Yellowstone National Park.
The park is known for its geysers and wildlife that roam freely near the thousands of park visitors each day. This picture was shot with an 800 mm (extreme telephoto) lens at a safe distance.
In honor of this year's National Park Service centennial, the Travel section is posting 100 park travel ideas and tips based on trips staff travel writer Christopher Reynolds has taken, along with photo-op advice from Times photographer Mark Boster. We'll post one per day through Dec. 31.
Follow Reynolds on Twitter: @MrCSReynolds
See travel videos by Reynolds from around the world.