Thought Experiment

Here's the question for today. Let's say someone has told you that tomorrow morning you will dropped at a randomly chosen place on one of Earth's land masses and you have to make your way back home. You get to wear whatever you choose in terms of clothing, but you only get to take one other man-made thing with you. What would you choose? A knife or other weapon, perhaps? A satellite phone? A Visa card? Other than those three, I can't think of anything else that would be a reasonable choice.

The chances are good you are going to end up in a very inhospitable environment. About a third of the land masses are either mountain ranges, deserts or capped with ice. Even if you hit the two-thirds that is mostly habitable, odds are you aren't going to be anywhere near a city or town of any size. So what item would be most useful to you?

The satellite phone is a fine option because you can immediately call for help. But if you don't know where you are, how can you tell people how to find you? (Though I suppose the authorities could probably track the phone signal to you, if you could convince the authorities it wasn't a prank before the battery ran out.)

A weapon is also useful, especially if you end up dropped in an inhospitable environment where you might face wild animals or even human threats. I suppose you could also use the weapon to obtain money or goods through the threat of force, but you would also likely run into people with bigger and more weapons who might thwart this plan of action.

I think a strong case can be made that a Visa card could be the winner. It may be of little use in a jungle or in a desert, but once you got yourself to almost any sort of settlement, it would be a widely-recognized symbol that you would be able to pay for the assistance you are requesting and would be greeted with more warmth (and likely equal respect) than you would brandishing a weapon.

Anyone else have any ideas?