In the early 19th century, the Arch of Konstantino-Elenensky gate was paved with bricks, but the Spassky Gate was the main front gate of the Kremlin and used for royal entrances. From this gate, wooden and (following the 17th-century improvements) stone bridges stretched across the moat. Books were sold on this bridge and stone platforms were built nearby for guns – "raskats". The Tsar Cannon was located on the platform of the Lobnoye mesto.