Well visible castle ruin with its walls peaking to the sky, you should not miss the view from the very top. Wachau valley will open in front of you with great view of Göttweig Abbey, world famous baroque blue tower right beneath you along with slopes bearing one of the best white wines in the world. And one can try to imagine what Richard the Lionheart was thinking while being kept here on his way back home..
Take some water with you, as it is a bit of a walk and summer can be pretty hot.
If you are on bikes, you can leave few of them just down in town where the shorter steep path starts and take off from there plus have a look at the nearby cemetery, there is a small church with some bones on display at the basement j:)