Once part of Staré Mesto's system of fortifications, the Old Town Powder Tower (as opposed to the Powder Tower in Prague Castle) was built in 1475 as one of the walled city's major gateways. The 42m-tall (138-ft.) tower marks the beginning of the Royal Route, the traditional route along which medieval Bohemian monarchs paraded on their way to being crowned at Prague Castle. It also was the east gate to the Old Town on the road to Kutná Hora. The tower was severely damaged during the Prussian invasion of Prague in 1737.

The present-day name comes from the 18th century, when the development of Nové Mesto rendered this protective tower obsolete, and it began to serve as a gunpowder storehouse. Early in the 20th century, the tower was the daily meeting place of Franz Kafka and his writer friend Max Brod. On the tower's west side, facing Old Town, you'll see a statue of King Premysl Otakar II, under which is a bawdy relief depicting a young woman slapping a man who's reaching under her skirt. The remains of the original construction are visible on the first floor above the ground.