Research reactors are constructed to provide support for a wide range of civil and commercial needs (e.g., generation of radioactive isotopes for medical purposes, neutron sources, reactor physics, etc.). Typically, these reactors operate at low thermal power levels (about 100 MWth) compared with commercial NPPs (about 3000 MWth). This presentation focuses on research reactors that operate at zero-power (several watts) levels. Zero-power reactors (ZPRs) have been there since the dawn of nuclear fission. The first ever reactor to reach self-sustaining chain reaction, designed by Enrico Fermi, the Chicago Pile No. 1 operated at a thermal power level of just several watts. Between 1942 and 1956, most of the constructed reactors can considered zero-power reactors, such as the French "Zoe", the Canadian "ZEEP" (Zero-Energy Experimental Pile), the British "GLEEP" (Graphite Low Energy Experimental Pile), or the Russian F-1 reactor. These reactors operated with one end goal: the atomic bomb. In 1953, President Eisenhower announced the Atoms for Peace program, which established the ground for the civil nuclear program for power generation and expanded the focus of research in those facilities. With the development of the civil nuclear program, there was a growing need for experimental facilities to study physics problems related to large reactors. Programs dedicated to Light Water Reactors (LWRs) under destructive conditions studies were performed in the Boiling Reactor Experiment (BORAX) and the Special Power Excursion Reactor Test (SPERT) in the middle of the 50's. However, since the nuclear renaissance years (60s-90s), hardly any reactor physics-dedicated facilities were constructed worldwide. Moreover, 2017 marked the final closure of Eole and Minerve, and 2018 the closure of Masurca (the last fast ZPR in the world). The presentation will look at the past of ZPR research facilities, with a focus on the UK case, provide some insight into future needs and showcase an ambitious future facility - the Zero-power Experimental PHYsics Reactor (ZEPHYR).