From CERN, Jan. 26, 2021: This week marks the 50th anniversary of the first proton collisions in CERN’s Intersecting Storage Rings, the first hadron collider ever built. To celebrate, see hadron colliders of the last half-century — including the Tevatron and the Large Hadron Collider — through a historical lens, with an eye toward the quest for high luminosity and new energy frontiers.