The Latin root of the word, oddly enough, means "an arrival," but adventure almost always involves a going out, and not just any going out but a bold one: Sail the ocean on a raft; pit your skills against a mountain; ride across a continent on a motorbike. It is a quest whose outcome is unknown but whose risks are tangible, a challenge someone meets with courage, intelligence and effort—and then survives!

There's seldom a shortage of applicants. Humans hunger for adventure, and most are voluntary—people.

But sometimes adventure is thrust upon us: An opportunity to test yourself or a chance of a life time will often arrive in some unsuspecting manner.

Such stories are as old as civilization. The Odyssey, the Viking sagas, and Sir Gawain and the Green Knight. And they all have mythological roots: Culture heroes go out into the unknown, endure various tests, bring back a boon—the Golden Fleece; the Holy Grail; the knowledge, at the very least, of strange new lands, strange new people.