The complex was designed by the firm of Graham, Anderson, Probst & White. Site preparation began in 1922, and approximately 2,200 buildings were demolished. Construction began in 1926, and structural work was completed by 1927. At the time, it was the second-largest excavation project in the world after the Panama Canal. The Terminal Tower opened to its first tenants in 1928. From its completion until 1964, the Terminal Tower was the tallest building in North America outside of New York City. Three other office buildings, the Medical Arts Building, Builders Exchange Building, and Midland Building, were built in addition to the Terminal Tower. The three Art Deco buildings are collectively known as the Landmark Office Towers Complex and were completed in 1929. In addition to the new buildings, the 1918 Hotel Cleveland was connected to the complex. Cleveland Union Terminal was dedicated and officially opened in 1930.