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.
10. Empire State Building's 103rd Floor Viewing Platform
King Kong swatted at planes from its summit, aliens blew it up in Independence Day, and it's been a fixture of the New York skyline since 1931. For these reasons and more, tourists have flocked to the Empire State Building for decades.
When taking in the stunning views from the viewing decks on the 86th and 102nd floors, it's easy to see why it's so popular among visitors to the city, but what most people who aren't Taylor Swift won't realise is that it's possible to go one storey higher.
Tay Tay was famously pictured on the Empire State Building's secret 103rd floor viewing platform in 2014, showing off her head for heights. This level is inaccessible to the general public for safety reasons. Only a small knee-high ledge and low safety rail separates visitors from the same drop King Kong plummeted down in 1933.
The tiny balcony can be reached via a series of elevators and a narrow metal stairway, but these days, you need to be famous to gain permission to visit it.