the union trust building was constructed in 1892-3. this structure, built in a "u" shaped plan with two wings surrounding a central light court, was designed by louis sullivan's firm immediately after their famous wainwright building. structurally, it is considered to be more pure than its better known contemporary (i.e., wainwright building). modifications of the first two floors in 1924 eliminated some of the buildings important architectural elements such as its arched entryways and circular windows. the upper floors of the building return to its original characteristics, with uninterrupted brick shafts from the third to the twelfth floors. above the rounded arch windows of the twelfth floor, a two story cap contains terra cotta lion heads projecting from its spandrels. rich sullivanesque ornamentation adorns the building's cornice.