High Quality Content by WIKIPEDIA articles! The Guardian Building is a skyscraper in downtown Detroit, Michigan. Today, the building is owned by Wayne County, Michigan and serves as its headquarters. Built in 1928 and finished in 1929, the building was originally called the Union Trust Building and is a bold example of Art Deco architecture, including art moderne designs. At the top of the Guardian Building's spire, is a large American Flag, complementing the four smaller flags atop nearby 150 West Jefferson. The building has undergone recent award-winning renovations. It was designated a National Historic Landmark on June 29, 1989.