Altgeld Hall is the architectural anchor of the UIUC campus — a Gothic Revival limestone building with a square clock tower that appears in the background of almost every campus photograph. It was the original home of the university library and now houses the mathematics department, which seems fitting for a building of its deliberate, vaulted seriousness.
The tower contains the Illini Carillon, one of the largest carillons in the world. Free public recitals are given by university carillonneurs on Friday afternoons during the academic year, and the sound carries across the Quad in a way that makes the university feel, briefly, like a medieval European college. The building's interior can be visited; the reading rooms on the upper floors have the quiet grandeur of an older idea of learning.