Jake M
Google
So much to see here! There are 5? main buildings, each housing different museums and (temporary, rotating) art exhibits. Costs €12 to visit 2 of any things of your choice or €24 to visit everything. But you can visit all the exterior fort for free! This is definitely worth it if you want a quick look and get a good view from the top of the Fort. If you want to visit the museums, you'll need a few hours to spare!
Our 2 choices were both in the Carlo Alberto building (at the top). We did the Museum of the Alps which has SO MUCH to see, and quite the diversity of history and information. This took us 2 hours and we didnt look too closely at half of it. Could definitely take 2-4 hours depending on your interests. Absolutely 1 of the best ways to spend a solid chunk of your day here.
2nd, we did the prisons downstairs in the same building. This was cool but much quicker (like 30 mins). It was a toss up between the prison and the Ferdinando building at the bottom.. unsure what all that offers or the time it takes to visit.
In total we spent about 3 hours here, and could have spent much longer if we got the full package. Lots of history here and offers a neat view of the valley. I would recommend it, but again, you'll need time if you want to visit any museums. I personally didnt care to visit any of the art exhibitions. From what I've gathered, they kind of have nothing to do with the Fort itself, so didnt seem worth any of my 2 choices.