There is a sound that can generally only heard by people under the age of 25. You may have heard that it has been used as a deterrent device to keep teenagers from loitering in malls and shops, and sounds similar to a buzzing mosquito.
Click here to find out if you’re under 25!
Comment with your results, especially if you’re over 25 and could still hear it or more worryingly if you’re under 25 and couldn’t!
My brother in law who is 34 could hear it but only when stood near to the computer, whereas I could hear it from far away.