At Old Faithful geyser, in Yellowstone National Park, benches are along the boardwalk in those areas with the best view of the geyser when it erupts.
Old Faithful is very predictable, to within ten minutes or so, most of the time.
If you haven’t had a chance to find out its predicted time, a full crowd on the benches is another good indicator that the geyser will be erupting soon. We were walking over from Old Faithful Inn parking lot and hadn’t checked the prediction time, yet.
This image was digitally rendered from a photo taken just before the 10:26 Old Faithful eruption on August 17, 2014.