Interesting tour of CERN. You can go into the Atlas detector building, but there’s no going down to the Hadron collider itself. It’s running now (April thru November) and there’s too much radiation. Guess that’s why it’s buried 100 meters down. The collider is 27 kilometers in diameter and there’s a proposal on the table to build another one to100 kilometers.
You can’t go down, but you can bicycle around the circumference of the collider tunnel, riding from Switzerland to France and back again, but parts of the path are rough and it’s a long ride. It’s also a reminder that as you pedal through fields and woods and pass by working farms, deep under your wheels are mysterious activities pushing the boundaries of science and technology.