Room temperature superconductivity (RTSC) is one the most challenging and longstanding problems in solid-state physics. The Bardeen–Cooper–Schrieffer (BCS) theory (1956) explained superconductivity but could not predict high critical temperatures (Tc). Extension of the BCS theory allowed RTSC in principle; however, estimations for realistic materials gave low Tc, with the only exception being metallic hydrogen. Therefore, conventional superconductors were not considered potential RTSCs. This tendency strengthened after the experimental discovery of superconductivity in cuprates with very high Tc, up to 133 K. Later, other families of nonconventional superconductivity appeared, notably, iron-based superconductors with Tc reaching 100 K. However, the mechanism of superconductivity in these materials is still not understood, and there has been no progress for many years in increasing Tc. Unexpectedly, conventional superconductors recently showed a clear prospect to be the first RTSCs: Tc = 203 K was discovered in H3S, and then Tc = 250 K in LaH10. This breakthrough resulted from a combination of factors, including the general idea to consider hydrogen-dominant materials, the appearance of ab initio predictions of structures for searching new materials, and advances in synthesis and characterization of new superconductors at megabar pressures. There is a clear prospect to achieve higher Tc in other binary or ternary hydrides. At ambient pressures, there is also a distinct possibility for substantial superconductivity, likely in materials with strong covalent bonding.