Mariano Moreno Plaza, to the east, is separated from Congressional Plaza (proper) by Montevideo Avenue, and was named in honor of Mariano Moreno, the intellectual leader of the 1810 May Revolution that led to Independence. A monument in his honor was unveiled in 1910. Moreno Plaza is also known for the symbolic "Kilometer Zero" marker put up by the Ministry of Public Works in 1935. Buenos Aires Mayor and Presidential candidate Fernando de la Rúa was on hand to unveil a nearby monument to his political mentor, the late centrist UCR leader Ricardo Balbín, in 1999. Moreno Plaza is best known to many as the site of one of the few surviving original casts of Auguste Rodin's "The Thinker". Commissioned by Museums Director Eduardo Schiaffino for the city in 1907, he and Rodin had envisaged its placement on a pedestal on the grand steps in front of Congress – a plan which never materialized. Currently, its transfer to its intended site is under consideration.