Minecraft is a $27 PC game. You can download and install it to your computer (for best performance) or even play it from a web browser. It's a little hard to describe, but basically it's an open world sandbox game where you can do whatever you want- explore, build structures, craft items, or fight monsters.
The game has a blocky, old school look. In fact, everything in the world exists as blocks, which you can move, stack dig through, or rearrange.
But here's the part I find really amazing- when you first start a game, a world is randomly created for you. Oceans, islands, rivers, forests, jungles, deserts, mountains, and caves. This whole unique living world pops into being, and it's yours to explore as you see fit. In the horizontal plane, the world is essentially infinite- you can't circumnavigate the world, and I don't think you can ever reach the end- the world just continues to generate as you walk.
Anyway, let me focus on the caves. There are some huge, complex cave systems in this game. And while they are created randomly, the way they are laid out seems to make sense and feel quite natural. Some of them reach the surface, some don't. Hill and mountain regions tend to have more caves, and you get all types- deep pits, small shelter caves, sea caves, and my favorite- the epic cave systems.
Here's a post I found on a video game forum of a person discovering a natural cave system while mining underground-
http://vine.rottentomatoes.com/vine/sho ... ostcount=1
(the pics really don't do the game justice- it's much nicer to see everything up and running in person)
But my best experience so far comes from deep underground. All of the best materials are found at depth, so I begin digging greedily, and too deep. At about 50 blocks deep, I cut through a last wall of rock before coming upon this scene: (picture).
Now, I realize that this might not look like much. But I actually let out an audible gasp as I stepped into this room. I had felt a sensation that I've only experienced a handful of times in my entire life: the shock of the new.
Most games have hidden secrets, little pockets of world that only the dedicated will find. But these secrets are all created, and with the intent of being found. They exist to please the gamer. But this room wasn't created. It was procedurally generated, the result of a mathematic algorithm. It didn't ever need to be found. I was incredibly lucky to even stumble upon it. If I had been digging 5 blocks to the left, I would have missed it completely, and it would have sat there for eternity, unseen.
It didn't need anyone to witness it in order to exist. I set foot into a room that no one had ever seen before, and although this may sound stupid, I felt incredibly lucky. I think it might be a little like how real explorers feel, when they came across something like the Grand Canyon. A place that is resolutely not for you. Something that wasn't created so that you could enjoy it. Something that just is.
That pretty much captures how I feel about caving in the real world. :)
Last night I broke into my first cave system, and it was awesome. Will type that story up in a minute.