As they prepare to celebrate a major milestone for Minneapolis' City Hall, city officials are looking for help from residents who might have their own piece of city history tucked away at home.

This summer marks the 125th anniversary of the laying of the cornerstone of the iconic downtown building, and the city is planning a public celebration for noon on July 11. First, however, officials are gathering historic items related to the building -- including at an event on June 23. People with items to donate -- documents, photos maps, or anything tied to the building's history -- can bring them to the City Hall rotunda between 10 a.m. and 2 p.m.

Items can also be donated at other times, by first sending an e-mail with a description and photo to archives@minneapolismn.gov. City staff members will assess the items and decide if they can be accepted.

The building was originally called the Minneapolis City Hall and Hennepin County Courthouse. It took 17 years to build -- it was completed in 1902 -- and cost $3.6 million.

Above: City Hall during an April 2015 thunderstorm. Aaron Lavinsky/Star Tribune