You can find Agravunde west of Riften:
Main Cave Puzzle
At the entrance you will run into Medresi Dran who is after the treasure at Agravunde. I chose to kill her to save future trouble when she might be expecting a blade in the back.
Anyway, Agravunde is mainly focused on solving puzzles. There are a few draugr around, but they are all fairly easy to kill because of their lower level. When you get to the main cave the way forward will be blocked by two main gates. You will have to complete side dungeons in order to go forward. The first that I went through is the one on the right side of the main cave. You can see a video explanation of this below.
Side Caves Puzzles
In that particular dungeon at some stage there will be spikes in the obvious way forward. You will find another doorway out of that small cave which you have to follow on a detour and evetually you will find a leaver that will lower all the spikes necessary. The small cave to the left of the main cave is even simpler. There are no puzzles to solve there.
Once you have pulled both the leavers and thus lifted the two gates it is a straight run to the wall with the word on it. I expected a final boss, but there isn’t one.
Full YouTube Walkthrough Video:
Below you can find a YouTube video that shows the entire dungeon with live commentary which explains what I was thinking about at the time and also post commentary to help with more difficult sections of the dungeon.