I have been to Kansas City many times. I'm sure you have, too. So would it surprise you to learn that there's an old, abandoned castle right near the bustling part of the city? Its true!
It's called the Kansas City Workhouse - it was built in 1897 as a prison. It was referred to as "the workhouse" because prisoners were sent their to live while spending their days doing manual labor in the community. But why build a medieval castle? Because during that time in popular culture medieval structures were considered trendy. It was also the desire of the state to make sure the building looked threatening to would be prisoners.
It continued in normal operations for a few decades but then closed and was reused for other state purposes. It was finally boarded up in 1972.
Since then, it has become a haven for graffiti art and curious onlookers. In recent years, plans have been set forth to turn it into a community center.
For more info, including where you can find it, here's a link.