“Tom Thumb,” a small geyser near the foot of the Lower Falls was historically accessible at the terminus of Uncle Tom’s Trail near the base of the cataract. Tom, an early private tourism purveyor, created the trail in the decades after Yellowstone was created. Subsequently, much having to do with resource protection and liability reasons, the National Park Service shortened and reconfigured the primitive trail as an iron stairway that no longer terminated at the river level. A new trail will make its debut in 2018. Photo by Steven Fuller