A Loop office building at 311 W. Monroe Street is pushing ahead with a major overhaul that will include Chicago’s first tenant-only bowling alley. Taking a page from the highly competitive residential market, the move illustrates how downtown office developers have doubled down on amenities as a means to stand out and attract a younger demographic.

In addition to the four-lane basement alley, property owner Sterling Bay plans to add new retail space, a fitness center, yoga room, and 15th floor tenant lounge that will open to the outdoors in warmer months.

The busy developer purchased the building last year for $61 million and was awarded a $19.6 million construction permit for interior and exterior renovations on Wednesday. Delivery is expected mid-2018, according to the project’s website.

Sterling Bay’s design, however, wasn’t the first plan to overhaul and reposition the 390,000-square-foot building. GlenStar, 311 W. Monroe’s previous owner, presented a proposal to gut the structure and reclad it in angular glass panels. Architecture firm JGMA also offered its own—more psychedelic—take on the corner.