Colossal Cave (at the top of the image) and the surrounding area leading to it.

For those of you who are too young to know, there once was an computer adventure game that was originally developed on a UNIX platform called Adventure. The game was completely textual and the goal was to explore a colossal cave, find and collect as much treasures as you can carry, and return home safe and sound (and possibly richer). It was great fun and was one of the first computer games ever created.

For you old timers, I hope you enjoy my vision of the cave entrance.