https://techcrunch.com/2019/01/15/cerns-plan-for-100-km-collider-makes-the-lhc-look-like-a-hula-hoop/

The Large Hadron Collider has produced a great deal of incredible science, most famously the Higgs Boson — but physicists at CERN, the international organization behind the LHC, are already looking forward to the next model. And the proposed Future Circular Collider, at 100 kilometers or 62 miles around, would be quite an upgrade.

The idea isn’t new; CERN has had people looking into it for years. But the conceptual design report issued today shows that all that consulting hasn’t been idle: there’s a relatively cohesive and practical plan — as practical as a particle collider can be — and a decent case for spending the $21 billion or so that would be needed.