Part 14: Chapter 14
>go in grate
Below the Grate
You are in a small chamber beneath a 3x3 steel grate to the surface. A low crawl over cobbles leads inward to the west.
The grate stands open.
Light lantern, enter grate, look.
You switch the brass lantern on.
Welcome to the cavern.
Lunch is over, so I'll be away for a while, but first:
Adventure: Behind the Parser
The caverns in Adventure are based on a real cave system called the Mammoth Cave in Kentucky. And when they say Mammoth, they aren't kidding. The cave system is one of the largest in the world (by some measures, the largest). Will Crowther's then-wife, Patricia, was actually on the team that found the connection between two large cave systems in the area, proving that they were all really one massive set of caverns.
The actual portion this game is based on is called the "Bedquilt" area. ("Colossal Cave" is a real cave in this system as well, but it isn't represented in the game.) The entrance was pretty much exactly as described here - a concrete plug in a large depression with a metal grate in it that leads down into the caves. Most of the initial rooms are laid out in the same way that they are in the actual caves, too; Crowther drew directly on his experience to make them. Of course, there are some fantastical elements as well, and there's a certain point where Woods' additions become, shall we say, more obvious...