Passman & Jones relocated to One Main Place, which was intended to be the first phase of a proposed three-phase “superblock” named Main Place. However, the other two phases of the Main Place development were never constructed due to financing. In 2015, One Main Place was approved into National Register of Historic Places as an important local example of modernist superblock architecture, where rather than filling a site from property line to property line, the building occupies only 25% of the total site, relieving the street wall and providing room for wide sidewalks and plazas.
The firm moved into One Main Place one year after the “Elm Street Cave” emerged. A giant hole emerged in 1967 on the south side of Elm Street, spanning almost the entire length of the block between Griffin and Field. Understandably, Elm was closed for seven months while the city investigated the cause of the hole and consulted with geologists on how to fix it. During the closure, the hole became a pseudo tourist attraction, even garnering enough attention for bumper stickers and t-shirts.