But how does it work? Have you ever thought about how that cat picture actually gets from a server in Oregon to your PC in London? We’re not simply talking about the wonders of TCP/IP or pervasive Wi-Fi hotspots, though those are vitally important as well. No, we’re talking about the big infrastructure: the huge submarine cables, the vast landing sites and data centres with their massively redundant power systems, and the elephantine, labyrinthine last-mile networks that actually hook billions of us to the Internet.
How the Internet works: Submarine fiber, brains in jars, and coaxial cables | Ars Technica