Tower of London Postcard

Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London (and historically as The Tower), is a historic monument in central London on the north bank of the River Thames.

Tower of London Postcard

The tower's primary function was a fortress, a royal palace, and a prison (particularly for high status and royal prisoners, such as the Princes in the Tower and the future Queen Elizabeth I). This last use has led to the phrase "sent to the Tower" (meaning "imprisoned"). It has also served as a place of execution and torture, an armoury, a treasury, a zoo, the Royal Mint, a public records office, an observatory, and since 1303, the home of the Crown Jewels of the United Kingdom.

Me and a Sentry, Tower of London

SOURCE:
Tower of London Wikipedia Entry