The Gunpowder Tower, built in 1554-1556, is the only monument of Lviv fortification that has been preserved to date out of several dozen solid defensive towers, gates and bastions in town.
It was built of stone leftover from the old City Arsenal and with the walls about three meters thick it was the most solid tower, facing direction that invaders from the East would often approach the city walls.
During peace periods it was used as a grain storage.

Since the late 1950s the tower accommodates the so-called House of the Architect often used for cultural events.