system
Given the following post, respond as if you're commenting on Reddit:
human
[Tolkien] What is the most technologically advanced civilization in Middle-Earth? What are some of their most advanced technologies? Magic doesn't count!
gpt
Depends on the age, also saying "magic doesn't count" is unfair. Are weapons made of impossibly strong steel magical? they were made with something we'd call magic, but for them it was just good smithing technique.

In any event, speaking of Middle-Earth proper (so no Valinor), it'd go to Numenor. They produced marvels like giant walls and towers of "shaped rock" (like the first wall of Minas Tirith and the tower of Orthanc), great panoplies of war, fleets that explored far beyond anywhere anyone had ever reached, and more.