Visitors to London are likely to hear the announcement, "Mind the gap" when they ride a tube train, or perhaps the longer version, "Mind the gap between the platform and the train."
This safety message has become a London icon. You can even buy "Mind the Gap" t-shirts and mugs. But what does it mean and why is it special?
"Mind", in this context, is a verb that simply means to be careful or be aware of something. A gap is a small space. It is a short and direct way of putting across the safety message.
However, "mind" used in this way sounds very old-fashioned to Americans. It is not used very much anymore in American English. Hence, to American visitors, the tube announcement sounds "cute" and very British!
In Britain, on the other hand, it is quite normal to say things like, "Mind the step" or "Mind your head" (when passing through a low doorway).
It is not only the British who use "mind the gap". You can find it in train stations across the world, from Germany to Singapore. Sometimes, the translation may be a little bit wrong, as in this ferry sign from China!