One of, if not the most unique "dungeons" I've ever visited in Skyrim. What did you think when you first entered? Also if you've never been there, look up the location on UESP.
I sadly knew what happened, as I looked it up - the quest marker for a fetch quest was telling me to go to Stony Creek Cave. Even so, I didn't think it would be that big a drop - died the first few times not being able to control falling properly