<P> The original entrance to the Great Pyramid is on the north, 17 metres (56 ft) vertically above ground level and 7.29 metres (23.9 ft) east of the centre line of the pyramid . From this original entrance, there is a Descending Passage 0.96 metres (3.1 ft) high and 1.04 metres (3.4 ft) wide, which goes down at an angle of 26 ° 31'23" through the masonry of the pyramid and then into the bedrock beneath it . After 105.23 metres (345.2 ft), the passage becomes level and continues for an additional 8.84 metres (29.0 ft) to the lower Chamber, which appears not to have been finished . There is a continuation of the horizontal passage in the south wall of the lower chamber; there is also a pit dug in the floor of the chamber . Some Egyptologists suggest that this Lower Chamber was intended to be the original burial chamber, but Pharaoh Khufu later changed his mind and wanted it to be higher up in the pyramid . </P> <P> 28.2 metres (93 ft) from the entrance is a square hole in the roof of the Descending Passage . Originally concealed with a slab of stone, this is the beginning of the Ascending Passage . The Ascending Passage is 39.3 metres (129 ft) long, as wide and high as the Descending Passage and slopes up at almost precisely the same angle to reach the Grand Gallery . The lower end of the Ascending Passage is closed by three huge blocks of granite, each about 1.5 metres (4.9 ft) long . One must use the Robbers' Tunnel (see below) to access the Ascending Passage . At the start of the Grand Gallery on the right - hand side there is a hole cut in the wall . This is the start of a vertical shaft which follows an irregular path through the masonry of the pyramid to join the Descending Passage . Also at the start of the Grand Gallery there is the Horizontal Passage leading to the "Queen's Chamber". The passage is 1.1 m (3'8 ") high for most of its length, but near the chamber there is a step in the floor, after which the passage is 1.73 metres (5.7 ft) high . </P> <P> The "Queen's Chamber" is exactly halfway between the north and south faces of the pyramid and measures 5.75 metres (18.9 ft) north to south, 5.23 metres (17.2 ft) east to west, and has a pointed roof with an apex 6.23 metres (20.4 ft) above the floor . At the eastern end of the chamber there is a niche 4.67 metres (15.3 ft) high . The original depth of the niche was 1.04 metres (3.4 ft), but has since been deepened by treasure hunters . </P> <P> In the north and south walls of the Queen's Chamber there are shafts, which unlike those in the King's Chamber that immediately slope upwards (see below), are horizontal for around 2 m (6.6 ft) before sloping upwards . The horizontal distance was cut in 1872 by a British engineer, Waynman Dixon, who believed a shaft similar to those in the King's Chamber must also exist . He was proved right, but because the shafts are not connected to the outer faces of the pyramid or the Queen's Chamber, their purpose is unknown . At the end of one of his shafts, Dixon discovered a ball of black diorite (a type of rock) and a bronze implement of unknown purpose . Both objects are currently in the British Museum . </P>

When were the great pyramids of giza discovered