The Seawell Ballroom at the Denver Center for the Performing Arts, built by the Denver office of Mortenson Construction, was the site of the contractor’s 30th anniversary party on Nov. 3. More than 550 people joined Bob Hansen, vice president and general manager of the firm’s Denver office, in celebrating its three decades of building landmark projects in Colorado. Those include the Pepsi Center, Coors Field, Concourse B at Denver International Airport, the new addition to the Denver Art Museum, Stapleton redevelopment, Research Complex 2 at the Anschutz Medical Campus and the Ritz Carlton Hotel. Denver Mayor Michael Hancock joked with the crowd that Mortenson, based in Minneapolis, would soon be moving its headquarters to Denver “because it has built most of the city anyway.”