I’d vote AC electricity to the cities. Indoor plumbing, then move to the modern age.
“I’d vote AC electricity to the cities. Indoor plumbing, then move to the modern age.”
A solid choice. Actually, it’s impossible to select a single greatest invention as each is predicated by a previous. An example; some say the ability to control fire was the single greatest invention. Some say it was the invention of agriculture and the domestication of animals. Some say the creation of permanent dwelling sites such as villages. Some say the creation of tribal rules which led to laws. But, each of these were enabled by a previous. So, how does anyone choose a single greatest? Can’t be done.