Namiestnikowski Palace - Presidential Palace.
It was built in the 17th century by the Radziwill family. In 1955 the Warsaw Pact was signed here; since 1995 it has been the official residence of Poland's president.
In the forecourt - a Bertel Thorvaldsen's equestrian statue of Prince Jozef Poniatowski (1763-1813), a nephew of the last king of Poland, Polish general, minister of war and army chief.
In 1813 he was nominated by Napoleon the Marshal of France, which was the only such distinction for a foreigner in France's history.
The bronze statue was made by Danish sculptor Bertel Thorwaldsen in 1832, but Russian tsar forbid to place it in Warsaw.
In 1922 the monument was erected finaly, but was completely destroyed during the WW II.
New mould, made by the model of the old one, was a gift from the inhabitants of Kopenhaag to Warsaw.

http://en.wikipedia.org/wiki/Jozef_Antoni_Poniatowski