The city of Savannah, Georgia, United States, was laid out in 1733 around four open squares, each surrounded by four residential ("tything") blocks and four civic ("trust") blocks. The layout of a square and eight surrounding blocks was known as a "ward." The original plan (now known as the Oglethorpe Plan) allowed for growth of the city and thus expansion of the grid; additional squares were added during the 18th and 19th centuries, and by 1851 there were 24 squares in the city. In the 20th century, three of the squares were demolished or altered beyond recognition, leaving 21. In 2010, one of the three "lost" squares, Ellis, was reclaimed. Most of Savannah's squares are named in honor or in memory of a person, persons or historical event, and many contain monuments, markers, memorials, statues, plaques, and other tributes.