"what happens when you type api.example.com and press enter?"
This has been one of my interview questions for years. Take a minute to speak your answer aloud. Do it now, I'll wait.
It requires walking through several layers and subsystems. Really a great question for exposing how the candidate models a complex system. The best part, as an interviewer, is seeing how deep the candidate goes down the potentially infinite rabbit hole.
The most entertaining answer I've received started with the electrical contact in your ENTER key sending the key code through USB. He briefly digressed into the pinout of PS/2 vs USB, and continued in that fashion.
there's at least one collaboratively edited doc about this standard interview Q; see https://github.com/alex/what-happens-when