Uglovaya Arsenalnaya Tower, Fortified tower in Moscow Kremlin, Russia.

The Uglovaya Arsenalnaya Tower is a fortified corner structure of the Moscow Kremlin that rises approximately 60 meters above the ground. The tower forms part of the Kremlin's outer wall and retains its massive stone construction, which once served as part of the complex's defensive system.

Built in 1492 by Italian architect Pietro Antonio Solari, the tower was set over a spring and included a well to supply the garrison during sieges. It guarded the crossing of the Neglinnaya River toward the Torg on Red Square. Damaged in 1812, it was repaired in 1817–18 following surviving drawings of its late-17th-century appearance.

The tower was called Sobakina for three centuries, probably after the nearby Sobakin boyar court; it took its present name from the Arsenal built behind it in the early 18th century. Inside, a narrow stone stair descends to the spring-fed well, the only one of the Kremlin's corner-tower wells still extant and often called Moscow's oldest.

The tower is best viewed during daylight hours when walking along the Kremlin's outer wall, which allows you to observe all of its details clearly. Comfortable shoes are helpful since you will be walking around the fortress perimeter to see it from different angles.

Inside the tower, a narrow stone staircase built under Solari leads down to a spring-fed well, the only one of the Kremlin's corner-tower wells still surviving and often called Moscow's oldest. In 1894 archaeologists pumped water out for a full day without emptying it; the inflow was measured at 10–15 litres per second. Excavations there later brought up 15th-century helmets, mail shirts and stirrups.