https://www.scientificamerican.com/article/physicists-lay-out-plans-for-a-new-supercollider/

CERN has unveiled its bold dream to build a new accelerator nearly four times as long as its 27-kilometer Large Hadron Collider—currently the world’s largest—and up to six times more powerful.

The European particle physics laboratory, outside Geneva, Switzerland, outlined the plan in a technical report on 15 January.