Chicago’s Navy Pier is currently undergoing major changes courtesy of a design team led by James Corner Field Operations. That work got an infusion of cash Thursday, as local benefactors from the Polk Bros. department store chain announced a donation of $20 million. It’s the single largest private gift ever made to Navy Pier, Illinois’ most-visited tourist attraction.

Their donation will support the redevelopment of 13 acres of the site, including Navy Pier’s entrance, Gateway Park. The park will be renamed for the Polk Brothers upon construction, which is expected to wrap up in time for the Pier’s 100th anniversary in 2016.

James Corner Field Operations’ plan for the new Polk Bros Park calls for two performance spaces and a 75-foot wide fountain that will serve as an ice rink during winter. Renderings also detail a wider promenade for pedestrian traffic and a welcome facility that will rent bikes. An “arts and culture plan” will be devised, said Bill Brodsky, chair of Navy Pier, Inc.—the nonprofit formed three years ago to guide the multiphase redevelopment. The plan is expected to detail how to feature art, plays, and other cultural programming originating from neighborhoods around Chicago.

Members of Navy Pier, Inc. were on hand to thank the Polks Thursday, as was 42nd Ward Alderman Brendan Reilly. Mayor Rahm Emanuel appeared to choke up as he compared the Polks’ early 20th–century immigration from Romania to his own family background, praising the appliance retailers as an embodiment of the American dream.

Though the project’s $115 million first phase is already under construction, Navy Pier’s makeover still faces hurdles. Redeveloping the Pier is a delicate undertaking, necessitating a mix of high design and sympathetic populism to sufficiently update the downtown icon without overwhelming the appeal it has as, to quote Daniel Burnham, “the People’s Pier.”