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Grand Gallery
Grand Gallery (with modern walkway up the middle)
The Grand Gallery continues the slope of the Ascending Passage towards the King's Chamber, extending from the 23rd to the 48th course (of stones), a rise of 21 metres (69 ft). It has been praised as a "truly spectacular example of stonemasonry".[162] It is 8.6 metres (28 ft) high and 46.68 metres (153.1 ft) long. The base is 4 cubits (2.1 m; 6.9 ft) wide, but after two courses – at a height of 2.29 metres (7.5 ft) – the blocks of stone in the walls are corbelled inwards by 6–10 centimetres (2.4–3.9 in) on each side.[80]
There are seven of these steps, so, at the top, the Grand Gallery is only 2 cubits (1.0 m; 3.4 ft) wide. It is roofed by slabs of stone laid at a slightly steeper angle than the floor so that each stone fits into a slot cut into the top of the gallery, like the teeth of a ratchet. The purpose was to have each block supported by the wall of the Gallery, rather than resting on the block beneath it, in order to prevent cumulative pressure.