This month marks 100 years since the first cornerstone was laid for Detroit’s majestic Masonic Temple, a hulking building at the corner of Temple Street and Second Avenue in Detroit’s Cass Corridor that constructed by the Freemasons, a spiritual fraternity with lodges across the world dating back to the 13th century. Constructed for $6.5 million at the time (about $87.9 million in today’s dollars), Detroit’s Masonic Temple also happens to be the largest in the world, boasting 16 floors and 1,037 rooms, some of which were never completed. We recently took a tour of the building — here’s everything we saw.