In the archeological museum in Athens, they have the recovered pieces, and a number of videos and modern replicas to try and explain how it works. It was very cool to see something like that in real life - not only the mechanism representing a tremendous amount of skill and craftsmanship, but the knowledge of how to precisely measure out decades-long patterns of celestial movement and fit them all together. Things like figuring out a slight irregularity in the pattern of the moon, and then figuring out a way to put gears together to replicate the same irregularity - and creating a device that would have been usable centuries after their lifetimes (if it hadn't sunk to the bottom of the sea, of course!)

That said, the most exciting thing for me to see there was definitely the Linear B tablets, with some of the earliest texts on them that we can understand. All in all, a wonderful collection of artefacts.