The Great Pyramid of Khufu is the only one of the seven wonders of the ancient world to have survived almost intact to our day. With its current height of 138 meters (146 originally), its 2.3 million stone blocks, and its interior galleries of stunning precision, it continues to defy our understanding after 4,500 years. Yet each decade brings new discoveries that renew our perspective on this extraordinary monument.1

The interior of the Great Pyramid is a masterpiece of engineering. The Grand Gallery, 8.5 meters high and 47 meters long, rises toward the King's Chamber at an angle of 26 degrees with a precision that rivals modern techniques. The King's Chamber itself, built of Aswan pink granite, is topped by five relieving chambers designed to distribute the colossal weight of the masonry above. The entire system of galleries and shafts testifies to an architectural planning of remarkable sophistication.2

The Great Pyramid of Khufu seen from the Giza plateau
The Great Pyramid of Khufu viewed from the Giza plateau: the sole surviving wonder of the ancient world, it retains at its base some courses of the white Tura limestone casing that originally covered it entirely.

In 2017, an international team announced the discovery of a large unknown void inside the pyramid, above the Grand Gallery, using muography - a method that uses cosmic muons like X-rays on the scale of a building. This "big void" measures at least 30 meters in length and represents the most significant unknown structure discovered in the Great Pyramid since the 19th century. Its function remains mysterious.3

Since 2023, the ScanPyramids project has continued its investigations with new technologies: radar, lidarLiDARLaser-based remote sensing (from "Light Detection And Ranging"): a sensor fires light pulses and measures the echo's return time to map a surface in three dimensions. Mounted on a plane or a drone, it slips through gaps in the canopy and reconstructs the bare-earth relief, revealing structures invisible beneath vegetation.→, and next-generation muography. Researchers are trying to determine whether other hidden spaces exist and whether the "big void" might contain a burialBurialThe intentional deposition of a body, sometimes with offerings; a marker of symbolic behaviour.→ chamber or a specific architectural structure. The pyramid of Khufu, humanity's eternal enigma, has not yet revealed all its secrets. This SLICE Histoire documentary traces what we know and what we are still searching for in the last wonder of the world.4