Mihulka, Fortified tower in Prague Castle, Czech Republic

Mihulka is a round defensive tower that protected the northern side of Prague Castle, equipped with loopholes for cannons on its lower levels. The structure rises through multiple stories and reveals how medieval fortifications were designed for combat.

Benedikt Rejt designed the tower, built in 1496 under King Vladislav II as the largest cannon tower of the castle's northern fortifications. After a fire in 1541 it was rebuilt as the home and workshop of the bell-founder Tomáš Jaroš, who cast the 18-tonne Sigismund bell for St Vitus Cathedral. Under Rudolf II it housed an alchemists' workshop.

The tower's name Mihulka is documented in Czech sources, and its later name Prašná věž (Powder Tower) comes from its use as a gunpowder store until 1754. Since December 2004 it has held a Military History Institute exhibition on military headgear and helmets, later replaced by one tracing castle military units from the beginnings of Czech statehood to the Hradní stráž.

The tower stands on the northern side of Prague Castle above the steep slope of the Jelení příkop. Its windows facing the moat were walled up from 1982 until 1990 to block the view toward the president's residence. Inside, the exhibition is reached by several staircases.

The tower's windows facing the Stag Moat were walled up after its 1967–1980 restoration so visitors could not look north toward the residence of President Gustáv Husák; they stayed sealed until 1990. Since December 2004 the tower has held a Military History Institute display on military headgear and helmets.