Falaise Castle is located on the edge of a cliff overlooking the Ante river valley in Normandy. It is not known when the castle was first built, but it is recorded as being the birthplace of William the Conqueror around 1027.
Much of the castle that exists today was built by William's son, Henry I, who also built the square Grand Donjon (or "Great Keep") in the 1120's. A wing on the west side (the "Petit Donjon, or "Little Keep") was added later in the 12th Century. The round tower was added around 1207 by the French king Phillppe II after the Duchy of Normandy was annexed by France.
Some features of the Grand Donjon suggest that there may have been a wing on the east side to protect the entrance but, if it existed, what it may have looked like is unknown.
I have only reconstructed the keep of Falaise, the castle itself lies to the east and south of the keep.
The Donjon of Falaise Castle is about 35 x 28 inches (112 x 88 studs) and is about 22 inches high. My reconstruction of the parapets and crenelations is speculation based on other castles built about the same time.
For more photos of my reconstruction of the Donjon of Falaise
For photos of the real Donjon of Falaise and other source