The Grand Place or Grote Markt is the central square of Brussels. It is surrounded by guildhalls, the city's Town Hall, and the Breadhouse. The square is the most important tourist destination and most memorable landmark in Brussels. It measures 68 by 110 metres (223 by 360 ft), and it is a UNESCO World Heritage Site.
In the 10th century, Charles, Duke of Lower Lorraine constructed a fort on Saint-Géry Island, the furthest inland point at which the Senne river was still navigable. This was the seed of what would become Brussels. By the end of the 11th century, an open-air marketplace was set up on a dried-up marsh near the fort that was surrounded by sandbanks. The market was called the Nedermerckt, or Lower Market.