Millennium Partners cleared a key financial hurdle with the city of Boston Thursday in its plan to build another downtown skyscraper.

The developer closed on its deal with the city to buy the property that once housed the Boston-owned Winthrop Square Garage, Millennium. The developer expects to immediately begin construction on the $1.3B, 691-foot mixed-use project, the Boston Globe reports. The deal includes a $102M payment to the city. While the total deal is expected to be around $163M, the next payment is tied to sales volume with the condo portion of the tower.

The project faced severe criticism over potential shadows it would cast on Boston Common and the Boston Public Garden as well as the impact its original 775-foot design would have on flights at the nearby Logan International Airport. After a lengthy review process, Millennium responded with the plan for a shorter tower.

Millennium began demolition and site preparation work in December while debate over the final design continued in a series of neighborhood meetings. The final look, which got approved in May, gives the 1.6M SF project a twin tower look from certain angles.