Built for the pharaoh Khufu about 4,500 years ago, the Great Pyramid at Giza is considered a wonder of the ancient world.

The ancient Egyptians created a simple yet elaborate system of blocks and grooves within the Great Pyramid of Giza to protect the King's Chamber from tomb robbers.

In an upcoming episode of the Science Channel's "Unearthed," that system comes to life via computer animations. In the episode, Egyptologist Mark Lehner describes the system for viewers, calling it a "very primitive machine." Lehner leads Ancient Egypt Research Associates (AERA), a team that has been excavating at Giza for about 30 years.

Many scholars believe that the King's Chamber housed the remains of the pharaoh Khufu (reign ca. 2551–2528 B.C.), the ruler who ordered the construction of the Great Pyramid of Giza. The tallest pyramid ever constructed in Egypt, the Great Pyramid was considered to be a "wonder of the world" by ancient writers. In addition to the King's Chamber, the Great Pyramid contains two other large chambers, which are today called the Queen's Chamber and the Subterranean Chamber.

What those two chambers were used for is unclear.

To protect the pharaoh's chamber, ancient Egyptians constructed a series of grooves and blocks that are hidden beneath the walls of the pyramid. While scholars have known about this system since at least the 19th century, the TV show uses computer animations to present a reconstruction. The animations show how blocks were dropped down grooves near the King's Chamber after the pharaoh' burial. [See the Reconstruction of the 'Primitive Machine' in the Great Pyramid]

Just outside the entrance to the King’s Chamber (hidden within the Great Pyramid of Giza), workers carved out a set of grooves and fitted three huge granite slabs (red arrow) into them. Once the king’s mummy was safely inside the chamber, the workers dropped those down to block the entrance. (Image credit: The Science Channel, screengrab)

The system was sophisticated for its time, said Lehner, noting that it blocked off the entranceway to the King's Chamber with giant blocks, making it harder for a thief to break in.

Even so, the machine did not protect Khufu's tomb. Today, all that remains of Khufu's burial is a red, granite sarcophagus. The chamber was "probably already robbed of its contents sometime between the end of Khufu's reign and the collapse of the Old Kingdom [around 2134 B.C.]," wrote Lehner in his book "The Complete Pyramids" (Thames and Hudson, 1997).

The ancient workers then fit three large granite blocks (bigger than the ones that fitted into the grooves; red arrow) and slid them down a chute to block the entrance to the passageways below the King's Chamber, essentially cutting off access to the so-called inner sanctum. (Image credit: The Science Channel, Screengrab)

A few Egyptologists believe that Khufu may have outwitted the looters with another tactic, however. In addition to the security system, the pyramid also contains four small shafts: two that originate at the King's Chamber and two more that originate at the Queen's Chamber. Robot exploration of the shafts has revealed what may be three doorways with copper handles.

Egyptologist Zahi Hawass, Egypt's former antiquities minister, told Live Science in 2013 that he thinks the shafts lead ultimately to Khufu's real burial chamber. The sarcophagus in the King's Chamber is simply a decoy, Hawass said, meant to fool looters into thinking that they had found Khufu's burial.

"I really believe that Cheops' [another name for Khufu] chamber is not discovered yet, and all three chambers were just to deceive the thieves, and the treasures of Khufu [are] still hidden inside the Great Pyramid," Hawass told Live Science in 2013. A project is currently underway to scan the Great Pyramid using a variety of technologies. Researchers in that project said they hope that if a hidden burial chamber exists, the scans will reveal it.

The episode of "Unearthed" that shows the system used to defend the King's Chamber will air Tuesday (July 12) on the Science Channel at 10 p.m. Eastern time.

Original article on Live Science.