The Corn Palace Built and dismantled every year since 1892. This is one of the world's most unique structures. It is an auditorium covered with real ears of corn intended to prove to the world that no matter what those people in Nebraska say, South Dakota is the best place in America to grow corn. The ears are arranged in different patterns each year, and inside there is a gallery showing the various designs over the years. Originally the corn played a larger role in the building's stability, but after a fire, the palace was rebuilt using steel and the corn is now applied to the inside and outside.
Entry is free, but most people stay outside.
If you venture inside to see the grand hall, you will be greeted by a site that is surreal. It takes quite a bit of willpower to convince yourself that the faint patterns dozens of feet in the air are really corn. It's only when you get close to a wall and can examine the ears individually that you realize the enormity of the task. In this case, a cowboy riding on the prairie. There aren't a lot of reasons to visit South Dakota, but this is one of the best.