Nikolska Tower, located on the eastern line of the Kremlin fortifications, is a passage tower with a quadrangular shape and an adjoining arrow slit. The gates of the arrow slit open onto Red Square. The tower was built in 1491 by architect Pietro Antonio Solari. The name is associated with the icon of St. Nicholas the Wonderworker, which was on the facade of the arrow slit, and with the Greek Nicholas Monastery on Nikolskaya Street. Like other passage towers, there was a drawbridge over the moat and protective grilles on the gates. The inner parts of the tower and the arrow slit are covered with cylindrical vaults, connected by a system of staircases and two-tiered corridors.

Nikolska Tower has preserved its ancient architectural forms longer than others. In the 16th and 17th centuries, its gates were mainly used for access to the boyar courtyards and monastery courtyards in the Kremlin. In the 1730s, the tower received baroque decor that harmonized with the design of the Arsenal and the Annengof Palace, creating a unified ensemble with them. In 1780, the tower was first topped with a round roof with a low tent. In 1806, architect L. Ruska completely rebuilt the tower, adding a Gothic octagon with lace decorations and a high tent.

In 1812, during the retreat from Moscow, the French blew up Nikolska Tower. Its restoration, based on the project by architect O.I. Bove, was completed in 1816-1819. At the suggestion of F.K. Sokolov, the white-stone tent was replaced with an iron one, and four white-stone pinnacles were installed at the corners of the square.

In 1917, the tower was heavily damaged by artillery fire, but was restored in 1918 under the guidance of architect N. Markovnikov.

Until 1935, the tower was adorned with a double-headed eagle, which was replaced by a star made of stainless steel, clad in gilded copper. In 1937, a ruby star was installed on the tower.

The height of the tower to the star is 67.1 m, and with the star, it is 70.4 m.