It's easy to assume humanity was always destined to become the planet's dominant species. But there was a time when our future hung in the balance—more so than you could ever imagine.

You spent weeks looking forward to strolling through a specific island town or checking a bucket-list destination off your list. Then, just before the ship arrived, the captain announced the itinerary had changed. It's disappointing, but the truth is that cruise itineraries are more flexible than many travelers realize, and there are rules that explain why.

Picture this: you've finally arrived at your vacation rental after a long day of traveling, and instead of punching in a door code, you're asked to scan your face. It can feel a little surprising if you've never seen it before. While facial recognition is becoming more common for short-term rentals, hotels, and apartment buildings, plenty of travelers are still caught off guard when it's suddenly part of the check-in process.