Spelunk!

I went caving with some friends this past weekend, and as we pondered a sign entitled "Speleology", one of them commented, "Don't you find it hard to believe that a word like 'spelunk' actually comes from, like, a Latin root?"

I did, so much so that I had to look it up (though the presence of the -ology suffix was a pretty good indication):

ETYMOLOGY:From obsolete spelunk, cave, from Middle English, from Old French spelunque, from Latin splunca, from Greek splunx.

But I also like the Calvin and Hobbes comic strip with the following dialogue:
Calvin: Want to go spelunking with me?
Hobbes: Spelunking? There aren't any caves around here!
Calvin: You don't need a cave. All you need is a rock. Spelunk!