1. Its First Inmate Helped Build It
The Tower of London served as a prison as far back as 1100, with the first known convict being a certain Ranulf Flambard. He was certainly an eminent inmate, being the Bishop of Durham as well as the chief tax collector. Rather ironically, his role as a construction manager meant he'd been responsible for building a wall around the White Tower - the central keep of the Tower of London, where he was to be imprisoned for financial extortion. He eventually escaped in spectacular fashion, using a rope smuggled to him in a gallon of wine. His friends who had arranged this also arranged for him to flee to Normandy, where he went into exile.
2. It Was Once Home To A Polar Bear
While the Tower of London has held many people captive over the centuries, it's also seen its fair share of animals. Records show that lions were first kept at the Tower in 1210, and the so-called "Royal Menagerie" would go on to boast quite an array of beasts, including King Henry III's pet polar bear, which was apparently allowed to wander out and catch fish in the Thames. There was a darker side to the Menagerie, though - bears and dogs were made to fight each other for the viewing pleasure of King James I, while a woman called Mary Jenkinson was reportedly mauled to death by a lion in 1686.
3. There's A Question About The Ravens
There is a degree of controversy over the legend that the kingdom will fall if the ravens ever depart the Tower of London. The accepted story is that it was Charles II who decreed that six ravens be kept in the fortress to safeguard the nation. Yet, more recently, some historians have come to believe it to be nothing more than a myth forged by romantic Victorians. Nevertheless, the ravens are still kept there, and are "enlisted" in the same way as soldiers.
4. The First Valentine's Message Was Written There
The first proper Valentine's love note was written by an inmate of the Tower of London. He was Charles, the Duke of Orleans, a Frenchman who'd been captured at the Battle of Agincourt. During his decades of rather comfortable captivity, he produced a good amount of poetry - including some love-struck lyrics written to his wife in 1415 while he was at the Tower, and which addressed her as "my very gentle Valentine".
5. The Ceremony Of The Keys
Centuries old superstition isn't the only thing that still runs strong in the Tower of London - tradition does too. The Ceremony of the Keys is a 700-year old ritual that occurs every single evening at precisely 9.53pm, when the tower is being locked up. During the process the Chief Yeoman Warder and an escort of men go about locking various gates, and as they approach a guarded post, a voice will shout out "Halt! Who comes there?" The Warder replies "The Keys", and a carefully scripted exchange ensues. This tradition has never been missed - though it was delayed by a few minutes during World War II, because of an untimely bomb explosion.