Built between 1895 and 1899, Altgeld Hall was originally called the "Castle on the Hill," built by Charles E. Brush of Chicago. The general contractor was William J. McAlpine. Construction started on September 17, 1895 and was completed on September 22, 1899 at a cost of $230,000.
When Altgeld Hall first opened, it housed the entire university. It was a classroom, boardroom, library, gymnasium, administrative office building, and lecture hall. It housed chemical and physical laboratories, executive offices, a 1,200 seat auditorium, biology labs, a study hall, a museum, and classrooms.
Altgeld Hall underwent a $24 million renovation project which began in 1999 and ended with the rededication on October 7, 2004. The Altgeld restoration was undertaken to rescue the university’s landmark structure, which was badly deteriorated. The interior of the building was remodeled several times over the years, but major structural problems went largely unaddressed.
A time capsule was buried under the front arches on NIU's 75th Anniversary in 1974. It will be opened on the 150th anniversary in 2049. (Wikipedia)