A great part of this massive stockpile of land needed to be converted into cash by the railways to finance their building activities, since railroad construction was a costly undertaking. New settlement had to be attracted to the virgin lands west of the Missouri River, which had been previously regarded by the public as worthless to the needs of agriculture due to insufficiencies of the soil as well as the arid climate. Millions of advertising dollars were spent by the railway companies promoting the agricultural development of the land which they had to sell. Populations skyrocketed and marginal lands were sold and settled.