The castle is a ruin you climb the hill for a FABULOUS view of the Wachau Valley and the Danube River. Claim to fame for this castle is that Richard the Lion Hearted was imprisioned after the Crusades here. Tip: there is a paved path which is much easier to climb than the rough steep path facing the river.
Durnstein is a very small village of less than 1000 inhabitants the other landmark is the blue spired Augustine Abbey Church which is stunning especially at night.

To the cycling enthusiasts I went with, the "old" path up to the castle was no problem, but if you are older, short, out of shape or have bad knees, make sure you take the new path. It is wide, paved most of the way and has interpretive signs along the way. I can't say that it is any steeper because it goes to the same place, but it is a slope rather than some combination of rough, uneven stone stairs, tree roots and the occasional hillside scramble. Those afraid of heights should not be too concerned either way, and the old way does have an occasional view of the river, but the views are best from on top the castle, where the fear of heights can become a problem – another good reason to at least go DOWN the new way, as I did.

As you face the town from the river, the new path is on the right hand side of town and plainly marked. The old way starts in the middle of town, down the old Main Street to your left. Your choice. Either way, leave plenty of time to get up and back before dark, but if you have the opportunity, stay into the night and see the beautiful way the old castle is illuminated.

If you're in decent shape and you can handle a steep 20 or 30-minute climb, you'll be rewarded by arguably the most spectacular views of the Danube to be found anywhere. From the top, you can see neighbouring villages and the river winding under steep hills so make sure you have your camera with you. As for the castle itself, the ruins are small and scattered but this is where Richard the Lionheart spent some time so it's of significant historical relevancy.

It sure took some doing going up the mountain, but it was well worth it. I'd say it only took 30 min or less. I went up the steep route from the main street in town, next to the cemetary. The view from above is nice of the Danube and neighboring towns. You can see vineyards streching on for miles. It is amazing thinking of the history and time that had gone by. I'd like to see an old drawign of how the castle looked. All I've seen are the ruins.