Opened in 1860 as the world's largest opera and ballet house with 1,625 seats, the Mariinsky Theatre was known as the Kirov under the Soviets. "Kirov" is still the name by which its ballet, opera and orchestra are known. A second concert space nearby opened in 2007 with seating for more than 1,000. The home of the Imperial Ballet and Opera under the tsars, it premiered such works as Mussorgsky's "Boris Godunov." In the 20th century, Pavlova, Nijinsky, Nureyev and Baryshnikov danced there.