Over 900 years of history can be explored at the Tower of London, a castle that plays the integral role in Britain's history. It's located in the east of Central London, besides both Tower Bridge and London Bridge.

The Tower of London has been the country's main fortress since it was built by William the Conquerer in the late 11th century. One glance at the domineering structure and square turrets quickly suggests why it has never been conquered. Over the centuries the Tower of London has also been a treasury, royal palace, armoury, menagerie, public records office, Royal Mint, prison, and famous execution site.

Much of this history is discovered on a guided tour. These are led by traditional Beefeater guards, who were first installed by Henry VIII in the 16th century; their resplendent style is apt for such a powerful fortress. They share many legendary stories while taking visitors to different parts of the Tower of London.

Included with a Tower of London entrance ticket is admission to the Crown Jewels Exhibition. Within a large room are the British monarch's main crowns and jewels, including the Imperial State Crown currently worn by Queen Elizabeth II. Other sparkling items in the collection are the world's largest diamond (317.4 carats), the 800-year-old silver Coronation Spoon, and St Edward's Crown. It can get very crowded in here during peak summer travel months.

Direct access to the Tower of London is from Tower Hill London Underground Station, or Tower Gateway on the Docklands Light Railway (DLR). When coming from South London it's also possible to alight at London Bridge Station and walk over Tower Bridge or London Bridge. Private ferry services also stop at St Katharine Docks, the same place where a small handful of famous figures went before their execution in the Tower of London, including two of Henry VIII's wives.

The Tower of London prison was used from 1100 until 1952, housing some of the country's most notorious criminals, along with a whole host of political prisoners. Guides reveal many fascinating stories of who and what became of them (only seven were beheaded here). The last two to spend time behind bars were the Kray twins, infamous London gangsters.