I worked at CERN a few years ago, so assuming they haven't build any new amazing facilities, these would be my top picks:

- Any of the experiments really, but especially ATLAS is impressive.

- The antimatter factory. I found that the guides there are usually very passionate.

- The control centre if you can get a tour (this is the facility I delivered software to).

I work for the control group at another accelerator, so we were visiting and meeting their control guys. Super friendly people all of them, they treated us like kings... and their control centre is bigger than our whole facility xD

So they allowed you to know that you are in the control group? Doesn't that introduce bias ;)

Sorry, I don't understand your comment :/

He was referring that in many experiments (especially in medical/biological) you usually have a control group, e.g. the group that is being given a placebo.

Took me a moment to understand it as well :)

Ah shit, you are right. I worked at a medical research center aeons ago so I should have known, but I am still dizzy from the jet lag xD

Thank you.

If you want to visit Atlas (control room) or CERN’s first accelerator (a synchrocyclotron) just show up in the morning when the visitor center opens. The tour guides are often passionate scientists. The museum is worth visiting, you’ll get to see the first www server (Tim-Berner Lee’s nextcube). The live shows are well put together. And everything is pretty much free of charge.

The only thing I can think of that has a waiting period is if you want to visit the actual tunnels, you can only visit them in between experiments (every 10-20 years maybe even less often).

That is great news. The last time I checked, there was a long waitlist and needed to book online (maybe COVID-related?). Appreciate you sharing this story.

This link might interest you: https://cms.cern/interact-with-cms/on-site-visits

If the timing works out for you, you'll be able to visit both, the visitor center and CMS!

Definitely will check it out. Thanks on a subatomic scale!

Can you visit CMS?

https://en.wikipedia.org/wiki/Compact_Muon_Solenoid

The presentations/videos talk extensively about CMS' detector (if I remember right). I'm not sure about visiting the control center, you would need to inquire if/when they do that.

Per https://cms.cern/interact-with-cms/on-site-visits, you can visit CMS if you book ~1 week out.

Thank you!