Complex sentence: Built to fund the civic and philanthropic activities of the Knights of Ak-Sar-Ben, the thoroughbred race track was built in 1920 and the Coleseum (capacity 7,200) was built in 1929.
Split into simpler sentences: Built to fund the civic and philanthropic activities of the Knights of Ak-Sar-Ben, Ak-Sar-Ben provided seating capacity for approximately 7,200. The track was built in 1920 and the arena was built in 1929.