The Horse's Pond was designed by Fischer von Erlach, a great Austrian architect in 1695. It was built because the festival hall was originally the royal stable, and in the horse's pond the horses were able to drink and were washed.
You can imagine what an important role the horses played at that time, if a master piece like that was dedicated to them.
Today the former stable is the Large Festival Hall with more than 2200 seats. Next to it is the Small Festival Hall, seating 1324 people and the Rock Riding School Festival Hall with 1550 seats.