My answer:
All this technology: Radios, Television, Pocket computers that you can just pull knowledge from that also perfroms the functions of various other gadgets which are also made possible by modern technology. And of course, THE INTERNET!
Standardization:
USB-C is awesome! :D
The world just uses AC power.
Metric system
Countries all around the world agreeing to a certain set of rules: Such as in Aviation, the world agreed to use Aviation English and standard phraseology, emergency frequency is 121.5, 3-Letter codes that is unique to every commercial airport in the world.
Treaties:
My favorite thing is the Kyoto Protocol [Edit: Montreal Protocol, mixed that one up]. We stopped the ozone from getting fucked. Now we need to do the same with climate change… 👀
Co-operation:
I was at a traffic light and it’s just amazing how (almost) everyone just follows the lights, and not just try to run red lights. Yay! (okay i know its just called “obeying the law” but still, I find this interesting)
International Space Station… (at least until a certain country withdrew… 👀)
Oh yes, you can basically lose so much water and salts you die of dehydration, that’s why people used to die from cholera. And drinking a lot of water won’t be sufficient, as you also need to replace the salts and sugars you eject. Today in the developed world our hospitals can just give saline solutions and let the patient “wait it out”, but it has not always been an option and probably still isn’t a lot of places in the world.