The three-sided glass tower on the Mulberry Union building opposite UCSF Medical Center on Parnassus Avenue houses a historical working mechanical clock designed by Seth Thomas that was salvaged from the old campus Medical School Building prior to its demolition in 1967. After a period of storage, the mechanism of the clock, which also tells the day of the week, was incorporated into the new five-story glass enclosure and dedicated on February 20th, 1982. A wall inscription reads:
Carried by ship around Cape Horn, this Seth Thomas clock was installed on the Medical School of the Affiliated Colleges in 1897. Surviving the 1906 earthquake, it served the University and community for 70 years. Members of the UCSF family have made possible its restoration as a campus landmark. February 20, 1982.