Moving a town is a big job. It took about 18 months, starting in 1925, and wasn't complete until 1927.
Individual houses were moved by truck. Larger buildings were put on rollers and pulled along a few inches at a time. The Methodist church was taken down brick by brick and reconstructed with the rest of the town on the hill above the river. The Lutheran church was moved in one piece. In the middle of the move parishioners simply propped a ladder up against the building, climbed in, and held services in the middle of the street.
When the reservoir began to fill, the only thing left of the old town of American Falls was a cement grain elevator, abandoned foundations, and a grid of roads and sidewalks. You can still see the lonely old grain elevator sticking up like a tombstone for the town when the reservoir is low.
One other thing lost as a result of the dam project--the waterfall that gave the town its name. The 25-foot American Falls of the Snake River is now a part of history.
The photo, courtesy of the Idaho State Historical Society digital archive, is of a two-story cement block building being moved to higher ground in 1925.