Tower of London (England)

The Tower of London (Tower of London) is the most beautiful medieval fortress of England. Started by William the Conqueror, it was built next to the Thames between 1066 and 1087 as a show of brute force and to demonstrate the power of the new masters of the kingdom (the Normans in the wake of William).
It was completed later by Edward I between 1272 and 1307.

We often talk about the Tower of London as if it were a single individual building, but in reality it is massive complex of palaces size, different shapes and functions, built over the centuries around what was to be the first building, the White Tower. The White Tower, stone, built inside the Roman walls was an excellent tower defense: 27 meters high, with thick walls 4 and a half meters and rooms for soldiers, servants and nobles.
It was built in about 20 years.

The tower originally served at the same time to protect the Normans from the inhabitants of the "City of London" and protects the city from outside invaders. William built the stone tower of Caen in northern France, and as an architect appointed the bishop of Rochester Gundulf.
Henry III later began the massive wall built inside and the moat, the closed and the actual zoo.
Edward I completed the interior wall, built the external one, some towers and Traitor's Gate and finally moved here the mint and the Crown Jewels from Westminster.

Stefano (1135-54) was the first king who lived in the tower,
James I (1603-25), the last after which Oliver Cromwell, demolished the royal residence. From here Edward I went in procession for her coronation and Henry VIII took off in procession in the City decked with gold drapes. In 1215 the barons seized the tower to force King John to affix his signature to Magna Charta. Always in the tower two princes were murdered on the orders of their own uncle
Richard III, while being crowned. Since 1485 the tower is guarded by a body of special guards, Yeoman Warders or "Beefeaters" calls they make also a guide (though only in English).

The Tower was for centuries the London prison for excellence, people had fear and respect. Generally was used to excellent characters, high-ranking and religious dissidents, or who, rich or poor had somehow caused offense to the British monarchs over the centuries. There were comfortable cells and other much less. The worst were those who stood at the level of the Thames, where the inmates were suffering from a devastating humidity.
In some cases when the river rises these prisoners could die drowned.