St. Isaac’s Square, decorated with an equestrian statue of Nicholas I in the centre, was designed by Piotr Klodt and completely remodelled by Auguste de Montferrand, the architect of the cathedral bearing the same name. Note the Miatlev House, at n° 9, the oldest house on the square, where Denis Diderot stayed, and the Town Hall Palace on the south side, now St. Petersburg’s city hall.