...one of the great art treasures of Europe. See it if you are at all interested in art. If any one of the panels was in a gallery somewhere it would be promoted as a must-see masterpiece - there are 37 of them, plus the end walls, the ceiling etc. The experience is a bit frustrating, with strictly timed 15 minute slots, but if that is the price to pay for seeing these stunning pictures, so be it, and it is preferable to the noisy scrum in some comparable places. Some practical tips:
book up your slot on the website as soon as you know when you can go - it does get booked up.
if you can get there early, there is a multimedia centre where you can see a film that is different to the compulsory one in the aclimatisation room (with an English language version)
the bookshop has a guide that includes reproductions and commentary on every panel, so if you really want to prepare for what you are seeing and have not had the chance before leaving home, you can read up on that as well - again, available in different languages.