Windmills used to be common on the prairies. They used wind power to bring water from the wells to the surface in order to water the livestock or to supply water for the farms. Many are still standing but most are down by now. Here's a photo of one in Saskatchewan that looks like it served the farm back when. It still has the wooden slats that caught the wind. Because they were made of wood they were not able to withstand the weather as well as the metal ones that came along later. So, that makes this one rather rare.