When planning the trip of a lifetime, most travellers are torn between seeing the most famous landmarks their destination has to offer and shunning them in favour of off-the-beaten-track exploration, but there is a way you can do both.
Some of the planet's most-visited tourist attractions play host to secret rooms and spaces, so well concealed that the thousands of people who visit these locations every day walk right past them, unaware of what is hidden in plain sight.
There's something about these secret rooms that captures the imagination, and this is even more true when they're tucked away in the world's most iconic buildings. Everywhere from the Empire State Building to the Eiffel Tower is concealing secret spaces, and discovering them might just be the highlight of your travels.
These landmarks, of course, aren't the only ones with something to hide. Famous man-made structures across the globe offer more than meets the eye, and therefore cater for mainstream tourists and those with a thirst for adventure alike.
From secret apartments up in the sky, to tennis courts tucked away at public transport terminals, these are the gems the world's best-known locations are hiding.