Mayfair is a district in central London, just east of Hyde Park, and one of the most expensive parts of the city. It is known for large hotels, luxury shops, private clubs, and embassies. It was once a very fashionable place to live in grand houses; many of those houses have since been turned into offices. People use Mayfair as shorthand for very rich, very posh London. In the British version of Monopoly, Mayfair is the dearest square on the board, which has helped the name travel even among people who have never been there. The name comes from a fair that used to be held in May on that ground; the fair is gone, the expensive address remains. Write it with a capital M: it is a place, not an adjective.