Eaton Square is a rectangular, residential garden square in London's Belgravia district. It is the largest square in London. It is one of the three squares built by the landowning Grosvenor family when they developed the main part of Belgravia in the 19th century that are named after places in Cheshire — in this case Eaton Hall, the Grosvenor country house. It is larger but less grand than the central feature of the district, Belgrave Square, and both larger and grander than Chester Square. The first block was laid out by Thomas Cubitt from 1827. In 2016 it was named as the "Most Expensive Place to Buy Property in Britain", with a full terraced house costing on average £17 million — many of such town houses have been converted, within the same, protected structures, into upmarket apartment