Harmugstahl is a fort found northeast of Markarth and west of Solitude. It is relatively small compared to some of Skyrim's labyrinth-like subterranean areas and is easily navigated. There is one puzzle in Harmugstahl with four levers controlling a metal barred/spiked passageway. There is one Adept locked door that needs to be picked. There are also two locked doors found after encountering Kornalus Frey; both can be unlocked with his key. In Kornalus' room there is a Shrine of Julianos and a few Alchemy ingredients.