The city of Dayton has changed a lot over time. In his book "Lost Dayton, Ohio" Andrew Walsh describes many of the forces that have impacted neighborhoods and buildings in the Gem City. Some of the things that have caused the greatest changes to the layout of Dayton and the structures in the city have been urban renewal, the construction of highways, and the massive destruction that was caused by the Great Dayton Flood of 1913. The book is filled with wonderful photos of forgotten neighborhoods