Merlion, Singapore (© sasint)

Long layover? We share below 7 airports offering free city tours!

Guggenheim Museum, New York, U.S.A.

There's only one rule to keep in mind when traveling: If you don't take photos, it didn't happen. (That, and don't drink the tap water. Okay, so two rules.) An un-Instagrammed Eiffel Tower may as well not even exist -- or, at least, you didn't see it. Yes, travel pics are important.

Berardo Collection Museum, Lisbon, Portugal - museuberardo.pt

We like to grumble, but when it comes to museums, we've got it pretty good in the UK, with free entry to many major museums.