The Circular Road to a Higgs Factory and Beyond

Over the past 50 years nearly 30 ring colliders have been built and operated successfully in various laboratories and countries. At the same time, an even larger number of storage-ring light sources with ever smaller transverse emittance have been constructed. Vast experience and highly refined expertise with ring colliders and storage rings have, thereby, been accumulated by the worldwide accelerator community.\nFor the next 50 years ring colliders are likely to remain the accelerator workhorse at the highenergy frontier, in the form of a next high-energy hadron collider after the LHC and an e^{+}e^{-} collider sharing the same tunnel, serving as precision Higgs factories and more.