At the top of the gallery, there is a step onto a small horizontal platform where a tunnel leads through the Antechamber, once blocked by portcullis stones, into the King's Chamber.

The Big Void
In 2017, scientists from the ScanPyramids project discovered a large cavity above the Grand Gallery using muon radiography, which they called the "ScanPyramids Big Void". Key was a research team under Morishima Kunihiro, a professor at Nagoya University, that used special nuclear emulsion detectors.[166][167] Its length is at least 30 metres (98 ft) and its cross-section is similar to that of the Grand Gallery. Its existence was confirmed by independent detection with three different technologies: nuclear emulsion films, scintillator hodoscopes, and gas detectors.[168][169] The purpose of the cavity is unknown and it is not accessible. Zahi Hawass speculates it may have been a gap used in the construction of the Grand Gallery,[170] but the Japanese research team state that the void is completely different from previously identified construction spaces.