On the average, Yellowstone National Park's Old Faithful blows every 90 minutes, shooting 4,000 to 8,000 gallons of water about 130 feet into the air. Patience is needed while you wait between eruptions, but you won't need any exotic lenses here.
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.