Here's a view through the top-surface exhibition paneling of Bill Buzbee's Magic-1 Homebrew CPU. He wire-wrapped thousands of pins to connect over 200 74 series TTL ICs to build a functioning 8-bit computer that runs with no centralized processor. Then he wrote, or ported an assembler, compiler, linker, text editor and operating system, the latter of which is based on Minix, upon which Linux is based.
This thing even serves a web page. Learn more, and access that page at his site.