6The falls of the Big Sioux River were formed 14,000 years ago, at the end of the last ice age, as melting ice eroded a channel down to the bedrock, revealing an abundance of Sioux quartzite. The power and beauty of the falls have attracted people to the area ever since, while Sioux quartzite has been used to construct many of the area's buildings. Incorporated as a city in 1856, Sioux Falls has steadily grown from a population of 17 at the time of establishment to 153,888 as of the 2010 census. As a natural part of that growth, change dictates that the old and worn out should make way for the new and shiny. Lest these things be forever forgotten, this book strives to point out what has been lost, what has been saved, and what can be found if one knows where to look.