To deter robbers from looting the tombs of great Pharaohs, ancient Egyptians may have constructed primitive machines inside the pyramids to defend royal funerary chambers. Archaeologists have digitally reproduced such protective mechanism used inside the Great Pyramid of Giza.

The digital model, which appears in an episode of the US Science Channel's series Unearthed, clearly suggests the ancient Egyptians were not just resorting to prayers to make sure their kings' final rest was not troubled by tomb raiders. Rather they took the time to think through and design an effective line of defence.

The Great Pyramid of Giza was constructed some 4,500 years ago and completed in 2560 BC under the rule of Pharaoh Khufu – a king of Egypt's fourth Dynasty. Some scholars believe that the King's Chamber inside the pyramid contains his royal remains.

A 'very primitive machine'

With the help of the digital reconstruction created for the documentary, Egyptologist Mark Lenher brings the defence system around the chamber to life and calls it a 'very primitive machine'.

The king's chamber is protected by very thick walls, some 80m thick. However, the passageways remain relatively unprotected, so the builders carved a series of grooves just outside the entrance of the chamber, hidden beneath the walls of the pyramid. They then fitted massive granite slabs into the grooves to effectively cut off the path of anyone who managed to walk deep into the pyramid.

Evidence of such a system has been known since the 19th century but, for the first time, the documentary shows how the granite blocks were dropped down the grooves, once the pharaoh had been buried and his grave sealed.

Understanding this security system might be a first step in leading archaeologists to discover new, hidden chambers. Some experts, such as Egypt's former antiquities minister Zahi Hawass, believe the tunnels and chambers which have been discovered up to now are 'fake' tombs, a trick to direct looters away from the real king's chamber.

Khufu's tomb could thus still be hiding somewhere in the depth of the pyramid. This 'trick' may be the most sophisticated defence mechanism of all – more effective perhaps to confuse tomb raiders than the granite blocks.

Pyramids of Giza
The defence system around the King's chamber was a 'primitive machine'Getty Images