The Great Pyramid of Khufu — also known as the Great Pyramid of Giza — is the largest of the Egyptian pyramids and the oldest of the Seven Wonders of the Ancient World, standing as the only wonder to have remained largely intact. Built c. 2600 BC for Pharaoh Khufu of the Fourth Dynasty over an estimated 26 years, it rises to approximately 481 feet and was constructed from more than 2 million limestone blocks. It anchors the northeastern end of the three main pyramids at the Giza plateau, part of the UNESCO World Heritage Site "Memphis and its Necropolis." For nearly 4,000 years it held the title of tallest man-made structure on Earth — a fact that still registers viscerally when you're standing at its base. Gates came here for Season 16 of Expedition Unknown to investigate some of the pyramid's most persistent mysteries: whether hidden chambers remain undiscovered inside, how ancient builders achieved such mathematical precision without modern tools, and what ultimately became of Khufu's mummy.
Construction of the Great Pyramid of Khufu begins, completed over approximately 26 years during the Fourth Dynasty of Egypt's Old Kingdom.
Pyramid believed to reach completion and serve as the royal tomb of Pharaoh Khufu.
Pyramid already ancient; visited and documented by early travelers and explorers across antiquity.
Scientists using muon tomography (remote sensing technology) claim to find evidence of anomalous voids inside the pyramid, reigniting debate over undiscovered passages.
Gates films S16E01 of Expedition Unknown, "Mysteries of the Great Pyramid," gaining rare all-access entry to investigate hidden chambers, construction methods, and the fate of Khufu's mummy.
Mainstream Egyptology holds that the Great Pyramid was built as a royal tomb for Pharaoh Khufu around 2600 BC, with construction managed by a highly organized workforce of skilled laborers — not slaves, as popular myth long suggested. The pyramid's internal architecture includes the King's Chamber, the Queen's Chamber, and the Grand Gallery, all connected by a system of ascending and descending passages. What remains genuinely puzzling even to professional archaeologists is the extraordinary precision of the structure: its sides are aligned to the cardinal directions with an accuracy of better than one-tenth of a degree, and its base is level to within just a few centimeters across its enormous footprint.
The question of hidden chambers has moved from fringe speculation into mainstream scientific inquiry. Muon tomography surveys — which use cosmic-ray particles to image dense structures the way X-rays image the body — have detected anomalous voids inside the pyramid that don't correspond to any known room or passage. These findings, published in peer-reviewed journals, have prompted ongoing debate among Egyptologists about what, if anything, those voids contain. Some researchers believe undiscovered passages or storage chambers remain sealed inside; others caution that the voids may simply be structural rather than architectural.
The fate of Khufu's mummy is a genuine open question in archaeology. No royal burial has ever been confirmed inside the pyramid — the granite sarcophagus in the King's Chamber was found empty — and Egyptologists continue to debate whether the body was removed in antiquity, hidden in a still-undiscovered chamber, or lost entirely. The episode also touches on a more recent internet phenomenon: claims by an Italian team that ground-penetrating radar had identified massive columns beneath the pyramid's foundations. Mainstream archaeologists have greeted such claims with considerable skepticism, noting that extraordinary evidence is required before rewriting what we know about the site's substructure.
Gates' S16E01 investigation brought cameras inside the pyramid alongside the latest scientific fieldwork, pairing his characteristically wide-eyed enthusiasm — "My god! It goes on forever!" — with on-site researchers conducting laser mapping and 3D scanning. The episode doesn't claim to have solved the pyramid's mysteries, but it honestly documents the live science being done there, making clear that the Great Pyramid remains, as Gates puts it, "humanity's ultimate monument and biggest mystery."
The Great Pyramid is the oldest of the Seven Wonders of the Ancient World and the only one that has remained largely intact.
Built c. 2600 BC, it held the record as the tallest man-made structure on Earth for approximately 3,800 years.
The pyramid is situated at the northeastern end of the line of three main pyramids at Giza and is the most famous monument of the Giza pyramid complex.
Muon tomography surveys — a technique that uses cosmic-ray particles to peer inside dense structures — have detected anomalous internal voids that do not correspond to any known chamber or passage, fueling ongoing scientific investigation.
The Great Pyramid of Giza is generally accessible to visitors as part of the Giza pyramid complex, located on the plateau southwest of Cairo. Tickets are required to enter the complex, with separate admission fees for interior access to the pyramid itself; the interior passages are narrow and can be physically demanding. Visitors should check current Egyptian tourism advisories and book permits in advance, as access to certain interior areas is sometimes restricted for conservation or research purposes.
Cairo, Egypt — approximately 13 kilometers (8 miles) northeast of the Giza plateau.
October through April offers the most comfortable temperatures for visiting, as summer heat on the Giza plateau can be extreme. Early morning visits are generally advisable to beat both midday sun and peak crowd volumes.
UNESCO World Heritage Site — "Memphis and its Necropolis" (inscribed 1979)
Kingdom of Kush Pyramid Tombs
Another Gates investigation into ancient pyramid cultures, exploring the monumental tomb architecture of the Kingdom of Kush in the same Nile-connected civilization sphere.
Ancient Egyptian tomb (Moses investigation)
Gates investigated Egyptian history and the ancient world in this Expedition Unknown episode, connecting broader questions about pharaonic Egypt and the biblical record.
Alexandria
Alexandria was a major center of Egyptian civilization and has been investigated by Gates in connection with the ancient world Gates explored throughout North Africa.
Historical data sourced from Wikipedia