single late 19th century copper-plated ornamental cast iron interior chicago stock exchange staircase stringer fragment executed by the winslow brothers, chicago, ills. the fragment retains the original copper-plated finish. the building's ornament was designed by louis h. sullivan, with the ironwork fabricated by the winslow brothers, chicago, ills. the chicago stock exchange building was built between 1893-94 and demolished, beginning in 1972. the downtown chicago financial district building had 13 stories and a single basement carried on pile and/or cassion foundations. the building had 480 offices and was adler and sullivan's largest commission after the auditorium.