The Tower idea first saw daylight towards the end of 1066 as part of the Norman Conquest of England. William needed to cnstruct defenses for his new realm. The White Tower which gives the castle its name, was built by William the Conqueror and was a resented symbol of oppression, inflicted upon London by the new ruling elite; a bit like the Bastille in France. The castle was used as a prison from 1100 until 1952. But has also been a luxurious Royal Palace for centuries too.
It has served variously as an armoury, a treasury, a menagerie, the Royal Mint and is still the home of the Crown Jewels of England.
The peak period of the castle's use as a prison was the 16th and 17th centuries, when many famous figures such as Elizabeth before she became queen, Sir Walter Raleigh and Margaret Pole were held within its walls. Ann Bolyn was executed there on Tower Green and a plaque marks the spot where she and others like poor old Margaret Pole met their end.
Royalty and nobles often has very comfortable lodgings just before execution. They arrived via the River Thames at Traitor's Gate. Some prisoners were in unpleasant lodgings and were tortured, such as Guy Fawkes. Most were executed nearby at Tower Hill. Rudolph Hess, Hitler's deputy, was held there for a while. The castle suffered bomb damage during WWII but was rapidly repaired and reopened as a key tourism attraction, as it has been for hundreds of years.
There's the infamous story of the princes in the tower who were probably murdered at the behest of their uncle Richard III who was seizing the throne after the death of his brother Henry IV. Skeletons were found of two boys and buried properly some years ago. The irony is that Richard was also found recently, unceremoniously lying under a carpark in Leicester, outside of London.he to has been reburied.
It must have been a wonder in the days when it housed the Royal Menagerie before zoos really existed, with lions and other exotic beasts and birds. These days there are only wire sculptured animals on display as remnants of a past exhibition. They are cleverly made from chicken wire.
There are still 7 ravens lving there and probably always will be as there's a saying that if the ravens leave the realm will fall.
I very much enjoyed this visit, arriving by a Thames cruise, being escorted around by a knowledgable yeoman warder. These guys are there to defend the place. They are all ex military service men and it's a sinecure for life. They have the right to be buried on site. Few others, apart from royalty through the ages, have had that right. You can catch the ferry back to Westminster if you wish. The Tower ramparts are also a great place to watch the Tower Bridge. I had the luck to be there just as it was opening for a small cruise liner.
For lots more info on the history of the Tower of London go to https://en.wikipedia.org/wiki/Tower_of_London