I think that glass is under-appreciated. Without it we would not have telescopes and microscopes (and all the scientific (and later engineering) that came from them), and later movies and photography—the latter also led to photolithography.

* https://en.wikipedia.org/wiki/Glass

* https://en.wikipedia.org/wiki/Telescope

* https://en.wikipedia.org/wiki/Microscope

* https://en.wikipedia.org/wiki/Photolithography

Nevermind the day-to-day quality of life improvements of eye glasses. Also:

* https://en.wikipedia.org/wiki/Optical_fiber

Would also need laters: modern communications would be much different if we still had to use copper cable (esp. over long distances), or microwave relays.