The Tower of London is a historic castle on the north bank of the River Thames in central London. It is located within the London Borough of Tower Hamlets, separated from the eastern edge of London by an open space known as Tower Hill. It was founded towards the end of 1066 as part of the Norman conquest of England. The White Tower, which gives the castle the name, was constructed by William the Conqueror in 1078, and was a symbol of resentful oppression in London by the new sovereigns. The castle was used since 1100 as a prison (Rainulfo Flambard was the first to be imprisoned) until 1952 with the Kray twin detention, although this was never its main purpose. At the beginning of its history, the palace also served as a royal residence. The tower is a complex made up of several buildings arranged inside two concentric wall rings and a moat. There have been several stages of expansion, especially during the reign of Riccardo Cuore di Leone, Enrico III and Edoardo I, in the XII and XIII centuries. The architectural design established at the end of the 13th century remains today, despite the various works that have been followed. The Tower of London played a prominent role in English history. Subsequent siege and its control has always been considered fundamental to the control of the nation. Throughout its history, the Tower of London has been used as arsenal, treasury, menagerie, Royal Mint's seat, public register office and jewelery seat of the Crown. From the beginning of the 14th century to the reign of Charles II, the coronation of a monarch was preceded by a procession from the Tower to the Abbey of Westminster. In the absence of the ruler, the Head of the Tower is the head of the castle. During the Middle Ages, this was a position of strength and confidence. Towards the end of the 15th century, the castle was the Prison of the Princes in the Tower. During Tudor's reign, the tower was used less as a royal residence, and despite attempts to restructure, its defenses became obsolete due to artillery developments. Between the sixteenth and seventeenth centuries, use as a prison had its peak phase, when many characters fell ill, like Elizabeth I, when it was not yet queen. This use led to the phrase "sent to the Tower". Despite its lasting reputation as a place of torture and death, popularized by 16th century religious propagandists and 19th-century writers, only seven people were executed inside it, before the two world wars. Executions were most frequently held on the famous Tower Hill, north of the castle. In the second half of the nineteenth century, institutions such as the Royal Mint moved outside the Tower of London, leaving many empty buildings. Anthony Salvin and John Taylor took the opportunity to bring the Tower back to its medieval appearance, clearing many of the vacant post-medieval structures. During the First and Second World War, the Tower was again used as a prison and there were executions of 12 men accused of espionage. At the end of the Second World War, the damage caused during the Battle of England was quickly repaired and the castle reopened to the public. Today the Tower of London is one of the most popular tourist attractions in the country. Under the ceremonial jurisdiction of the Tower Constanta, it is part of the Historic Royal Palaces and is protected as a World Heritage Site.