There are exactly two claims to fame here-
The Fort: Which, thanks to it’s strategic position, was coveted by practically every local ruler who wanted to strengthen his hold over the surrounding land. There’s clear evidence for Mandu being fortified for over 2500 years now. Though abandoned 400 years ago, the fortress gained some incredible architecture, not to mention an incredibly, dramatically, romantic story concerning Rani Roopmati. Indeed, the architecture is tied into this history. You’ll enjoy yourself much more if you read up on the story beforehand.
Nilkanth: This sacred Shiva shrine is sited in a magnificent setting, at the very edge of a steep gorge. In its tree-shaded courtyard, a sacred pond is fed by a stream, and pilgrims still gather to worship here.