Most of us will never get the chance to use wilderness survival skills. However, our chances of being stranded in an urban jungle with no wallet and no laptop are much higher. Laptop bags, luggage and wallets can get lost, stolen or destroyed while on the road. I know someone who had her carry-on luggage lost by the airline. Yeah, that's right: carry-on.

The reality is that stuff happens. And when it does, it's nice to be prepared. In this column, I'm going to tell you how to survive in any city with nothing but a cell phone.

Just like in the wilderness, when you're stuck in a city, your priorities are finding food, shelter and a way out—in that order.

Your Phone

To wilderness survivalists, a good knife is the necessary all-purpose survival tool. For urban survival, your cell phone serves the same purpose.

If you travel on business, make sure you buy a cell phone with long battery life, GPS, good Internet-surfing capability and removable media cards with plenty of storage capacity.

It's also nice to be able to charge your phone via standard USB cable, rather than via a proprietary connector. That enables you to charge your phone in cybercafés or hotel business centers if your laptop bag—and your charger—goes missing. You can almost always find someone who can loan you a standard USB cable.

It's also a good idea to download and install a secure-data application that password-protects important information, such as your credit card, frequent flier and other numbers, as well as PINs and passwords you may not remember. You should also back up all the documents you might need during your trip.

The single most valuable service you can use with a telephone is Google's GOOG-411 service. Put it on speed dial or memorize the phone number: 1-800-466-4411. The service is the fastest way to call any business, which saves both time and battery life.