10 best travel inventions of all time

— -- Many of the everyday conveniences that ease you through your journeys, from the hotel key card in your wallet to the website where you booked your trip, are responsible for revolutionizing the travel world. These seemingly commonplace goods and gadgets have had an extraordinary impact on the way we see the world—and we can't imagine hitting the road without them. Find out which 10 breakthrough inventions deserve credit for turning the travel sphere on its head.

Hotel key card

One powerful little piece of plastic has made hotel stays safer and more convenient for travelers. Magnetic key cards started appearing in the 1950s and have since become the standard means of entry at accommodations around the world. On the rare occasion that you're issued a traditional key at check-in (if you're staying at a small B&B or in a vacation rental, for example), you may be reminded of the great advantages of key cards. An unlimited number of copies can be made (one for each of the kids), the card can be replaced in an instant, and lost cards can be erased remotely. Bonus: The card fits neatly into your wallet.

Smartphone

If you want to listen to an audio tour, read hotel reviews, build an itinerary, or take panoramic photos, there's an app for that. (We couldn't resist.) But the best travel advantages offered by the smartphone may be soon to come. Apple has filed a patent on a tool that would allow air travelers to use iPhones to store valid IDs and boarding passes. This technology would work in conjunction with innovative airport security checkpoints that might use facial recognition technology or retina scans along with electronic identification stored on smartphones to move passengers swiftly through checkpoints. Soon, the smartphone could make hard identification, like driver's licenses or passports, obsolete.

Credit card

Credit cards first appeared on the scene in the 1920s but didn't gain popularity until the 1950s, when Diners Club and American Express issued their first cards. Those early credit cards were made of cardboard, mind you, and we've come a long way since then. Travelers now use credit cards to earn miles, get a more favorable exchange rate, and keep track of spending. But, more importantly, credit cards, with their range of built-in safeguards, are a far more secure alternative to cash and traveler's checks.

Travel adaptors and converters

Electrical standardization around the world—or lack thereof—has pretty much been the same since Edison and Tesla were around. The International Electrotechnical Commission (IEC) developed a worldwide standardized electrical plug, but only one country jumped onboard (Brazil). So at present, at least 12 major electric-plug types are widely used around the globe. And only one matches up with your hair dryer. But quite amazingly, two handy little gadgets are all you need to conquer the crazy variations of electrical systems around the world: the humble adaptor and converter. Without these, travelers would need a new set of electronic devices when passing through countries with different standards of electricity.

Digital camera

While some photographers are still faithful to film, anyone who's packed a suitcase can appreciate the space-saving virtues of the digital camera. With one at hand, we're free to record a nearly endless amount of travel images and, thanks to related digital technology, share them in a snap.