The Hamm Building, the iconic structure in downtown St. Paul, will mark its 100th anniversary Thursday –and the public is invited to come and celebrate.

Construction on the building began in 1915 with the intention of existing as a department store, but due to World War I and the lack of manpower and resources, work was delayed.

The Hamm family bought the building in 1919 to turn it into an office space, with construction finishing in 1921.

“It was kind of the place to be back in the day,” said property manager Kristel Hansen.

Thursday’s event — held 100 years from the building’s opening date — will celebrate Hamm’s retail presence, Hansen said. Today the building is home to multiple retailers and office spaces.

The six-story office building underwent a complete renovation in the 1990s, said Tim Dwyer, president of the Markham Company of St. Paul, which owns the building. Dwyer has worked in the building for approximately 50 years, both as president and as a public defender in one of the office spaces.

“St. Paul is a different place than it was 50 years ago…(The Hamm Building) is truly a wonderful building,” Dwyer said.

Thursday’s celebration, which is open to the public, will be held rain or shine from 2 p.m. to 6 p.m. and will include free food, music, themed tours and a history walk lined with old photos of the building.

Weather permitting, the plaza in front of the Hamm Building will also be used for the event, but organizers say there are plans in the works for taking the party completely inside due to the predicted rain.