What scientific discoveries, in your opinion, were the most significant and why?

It is likely that the invention of any of the types of engines can be attributed to those, because they made it possible to increase the intensity of production and, accordingly, accelerate transportation and movement by different types of transport. The discovery of electricity can be attributed to the same significant discoveries, which made it possible to both provide powerful artificial lighting for the population, and, accordingly, improve production, create various devices, and so on. If we take the 20th century, then all the same it is the discovery of penicillin and various vaccinations, which made it possible to save many lives.