The Josefov Fortress is a remarkable structure whose chequered past you will learn about on an engaging guided tour. It was built in 1788 on the orders of Emperor Joseph II, and its mighty fortification walls along with its underground corridors were meant to defend the Austrian monarchy against frequent Prussian incursions. The fort was a giant arsenal, a storehouse for gunpowder and supplies, and also provided accommodation for soldiers and civilians. A guided tour will take you through the tangle of underground corridors and familiarize you with the travails of military life. For the stout-hearted, especially children with their parents, haunted tours accompanied by gripping legends are held regularly.