For 600 years, a bell tower has always stood at the site of the Ivan the Great Bell Tower. Boris Gudonov ordered it to be heightened so that it would be the tallest building in Moscow. Until the 19th century, no buildings in Moscow were permitted to be taller than the the Ivan the Great Bell Tower. The tower was used both as a watchtower and as a bell tower. Twenty-one bells are suspended in the bell tower and at least two dozen bell ringers were needed to set the bells into motion. The Ivan the Great Bell Tower was one building marked for destruction by Napoleon, but his attempts to raze the bell tower failed.