As you walk along Simenstraße in Trier, Germany, and are admiring architecture that dates back centuries and even millenniums, you notice this colorful Moorish building because it seems so out of place. The Dreikönigenhaus was built in 1230 as a tower house for an alderman’s family. Notice the suspended door on the second level. This used to be its only entrance and was accessible by a retractable wooden stairs.