From the pre-production of the films, Peter Jackson had decided to create small-size models of structures to the last detail and then add some digital work, instead of creating these locations fully digital. Some of the Big-atures Weta created include:
Minas Tirith was built in a 1/72 scale and some of its parts in a 1/14 scale for closer scenes. According to the Extended DVD edition of The Lord of the Rings (film series), it required almost 1000 houses to be completed, and its height was around 7 meters.
John Howe revisited the original drawings based on Tolkien's writings, and the model was built on a rocky pinnacle instead directly on the mountain, Cirith Ungol constructed highly detailed with various gothic elements.