For at least 3,339 years, nobody has seen what lies behind the west and north walls of the burial chamber of Tutankhamun. But this secret of three millennia might not last much longer. 
 
 On Thursday, Mamdouh Eldamaty, the Egyptian antiquities minister, held a press conference in Cairo to announce a tantalizing new piece of evidence: Radar scans on those walls have revealed not only the presence of hidden chambers, but also unidentified objects that lie within these rooms. These objects, Eldamaty said, seem to be composed of both metal and organic materials. 
 
 “It could be the discovery of the century,” he said. Noting that he can’t speculate further about the things that lie within the chambers, he said that another radar test has been scheduled for the end of this month, in order to determine the best way to proceed with the investigation. 
 
 The results of the radar scan represent another step toward a radical new understanding of the most famous tomb in Egypt’s Valley of the Kings. First discovered by archaeologist Howard Carter in 1922, the tomb of King Tut yielded an astonishing array of grave goods—more than 5,000 artifacts, many of them in pristine condition. It was the most intact royal tomb ever found, providing Egyptologists with an unprecedented glimpse into the material life of a king who ruled during the 14th century B.C. (Read more about the pharoah who shaped the future of Egypt.) 
 
 View Images Hirokatsu Watanabe, a radar specialist from Japan, pushes his specially modified Koden-brand machine along the north wall of Tutankhamun’s burial chamber during radar scanning last fall. Photograph by Brando Quilicci, National Geographic 
 
 But for almost a century, nobody imagined that Carter’s painstaking excavation—he spent a decade documenting and clearing objects from the tomb—might be essentially unfinished. In July of last year, Nicholas Reeves, a British archaeologist who specializes in the Valley of the Kings, published a paper claiming that there may in fact be another tomb hidden behind the walls of Tut’s burial chamber. 
 
 Reeves’s theory was based in part on close examination of high-resolution laser scans of the tomb, which seemed to indicate traces of passageways and door openings that had been plastered and painted over during the preparation of Tut’s chamber. 
 
 Initially, Reeves’s paper was dismissed by many Egyptologists, but over the past half year, an ongoing examination of the tomb has supported a number of his key ideas. “I’ve not found anything that makes me doubt my initial conclusions,” Reeves said, when contacted by telephone earlier this week. “I guess we’re getting closer to a resolution now.” (Related: Will King Tut Fever Bring Visitors Back to Egypt?) 
 
 The radar results represent the biggest endorsement thus far. Last November, Eldamaty invited Reeves and Hirokatsu Watanabe, a Japanese radar specialist, to Luxor, where they spent two evenings conducting radar scans of the west and north walls of Tut’s burial chamber. An initial read of the scan was compelling: After those tests in November, Eldamaty announced that he was “90 percent positive” that another chamber lay behind the north wall of the tomb. But his comments were based entirely on the analysis of one man—Watanabe—and at that time the Japanese specialist had yet to conduct a detailed study of his data. 
 
 Thursday’s announcement, though, was based on Watanabe’s full report, which was delivered to the minister earlier this year. Eldamaty noted that the Japanese specialist believes there are objects made of metal and organic materials behind the north wall, and others composed of organic materials behind the west wall. “But I cannot say exactly what it is,” Eldamaty noted at the press conference. 
 
 View Images Pointing to his computer screen, Watanabe explains the multicolored bars that represent radar data used to determine the material structure of the walls. Photograph by Brando Quilicci, National Geographic 
 
 “There’s Something in There” 
 
 These radar findings have also been reviewed by outside experts. Remy Hiramoto, a specialist in semiconductors and microelectronics who has served as a consultant to the UCLA Egyptian Coffins Project, examined the raw data, along with some of his colleagues, including Adrian Tang, a strategic researcher who works at NASA Jet Propulsion Laboratory in the THz systems group. 
 
 When contacted by telephone earlier this week, Hiramoto described the data set as “tight” —he felt that Watanabe’s equipment had performed well in the tomb. “It validates the initial hypothesis that there is a non-natural occurring chamber or cavity on the other side of that wall,” Hiramoto said. “Based on the signatures that are in the data, there’s a void, and there’s definitely something that’s within the void. There’s something in there.” 
 
 Hiramoto said that he and his colleagues could not tell what those objects are made of, or what they might be—whether they are naturally occurring features, or grave goods, or something else. But he noted that reading a radar is “like a Rorshach test,” and such work tends to be highly specialized. 
 
 WATCH: New evidence supports the theory that King Tut's tomb has a hidden chamber, according to experts. 
 
 Jason Herrmann, who specializes in archaeological geophysics at Eberhard Karls Universität Tübingen in Germany, said that a radar expert can determine some details about unseen materials. “In my past experience I’ve been able to pick out metal versus stone pretty easily,” he said, noting that in the past he used radar to locate metal artifacts that were buried within sand dunes in the United Arab Emirates. He said that detecting a metal object in a stone-carved room should be easier than detecting it in sand. 
 
 “I’m not surprised that he’s able to pick out something that’s a weaker reflector than stone would be, or metal would be,” Herrmann said, referring to the possible presence of organic matter. 
 
 Later this month, a team of specialists from National Geographic will travel to Egypt at Eldamaty’s invitation, in order to carry out another series of radar tests, with the hope of confirming Watanabe’s results. At the press conference, Eldamaty mentioned that one of the main purposes of the new scan will be to determine the thickness of the walls, in order to decide the next step of the investigation. But he refused to say what that step might be. “We have to wait,” he said. 
 
 Signs Point to Queen Nefertiti? 
 
 Almost anything that comes to light behind the walls will force specialists to envision the age of Tut with new eyes. “It makes us re-look at everything,” said Kara Cooney, an Egyptologist at UCLA who has done extensive research on the 18th Dynasty, Tut’s period. She noted that one of the most explosive aspects of Reeves's theory is the idea that Nefertiti, who most people believe was Tut's stepmother, may be buried behind the north wall of the tomb. 
 
 As of yet there is no hard evidence for this theory, but a number of prominent Egyptologists have agreed with Reeves's suggestion that the famous funerary mask of Tutankhamun was originally fashioned for Nefertiti. And there are signs that many of Tut's grave goods were originally made for somebody else. ||||| A third round of ground penetrating radar (GPR) scanning is underway inside the burial chamber of King Tutankhamun, Egypt's Ministry of Antiquities announced today, as part of an effort to answer a question that has long intrigued and stumped researchers: Are the walls of the famous tomb hiding other chambers—perhaps another royal burial concealed for more than 3,300 years? 
 
 Ever since archaeologist Howard Carter discovered the treasure-packed tomb in Luxor's Valley of the Kings in 1922, experts have believed the space to be strangely small for a pharaoh. Various theories about the tomb have been proposed over the decades, but in 2015 Egyptologist Nicholas Reeves suggested an astounding possibility: The north and west walls might conceal the mummy—and fabulous possessions—of Tut’s stepmother, the legendary beauty Queen Nefertiti. 
 
 What King Tut’s tomb is hiding Stairway Scientists are investigating whether there are hidden chambers behind the north and west walls of King Tut’s tomb. 25 feet Treasury Antechamber Burial chamber Annex Hidden room? NORTH Hidden room? NG STAFF PHOTO: Kenneth Garrett SOURCES: THEBAN MAPPING PROJECT, Ministry of State for Antiquities What King Tut’s tomb is hiding Scientists are investigating whether there are hidden chambers behind the north and west walls of King Tut’s tomb. Stairway 25 feet Treasury Antechamber Burial chamber Annex Hidden room? NORTH Hidden room? NG STAFF PHOTO: Kenneth Garrett SOURCE: THEBAN MAPPING PROJECT. Ministry of State for Antiquities 
 
 Two previous scans of the burial chamber, conducted in 2015 and 2016, varied in their results and were determined inconclusive. A third non-invasive GPR scan was commissioned by Egypt’s Minister of Antiquities Khaled El Enany following the recommendation of experts who met in 2016 to study the results of the previous scans. This latest investigation, conducted under the direction of the Polytechnic University of Turin, aims to resolve those results and verify whether or not there are voids behind the walls. 
 
 Intriguing Clues 
 
 Reeve’s idea was prompted by a highly detailed 3D scan of the tomb conducted in 2009 by the firm Factum Arte, which was tasked with building an exact replica of the tomb for tourists to visit. When Reeves studied the scans of the north and west walls, he believed he saw traces of openings that had been bricked up and plastered over. Those features could help explain two other puzzling features. 
 
 In 1984 Egyptologist Gay Robins published a paper about the proportions of the figures painted on the walls of the burial chamber. On the north wall they followed a 20-square grid, but on the other three walls they followed an 18-square grid. Robbins thought that might have been the result of the rushed preparation of the tomb, which could have involved separate teams of painters trained in two different traditions. But what if the walls had been painted at two different times—after one burial was sealed, and then again when another burial was added some years later? 
 
 Experts from the Getty Conservation Institute in 2012 noticed something else that was strange. The background of the north wall was originally painted white but later repainted yellow to match the other three walls. Did the white background date to the first burial, and the repainting to the time of Tut? 
 
 When Mamdouh El Damaty, Minister of Antiquities at the time Reeves put forward his theory, took a close look at the north wall, he saw another irregularity in one area—a clear difference between two wall treatments. The upper part of that area displayed paint on bare stone, but the lower part was paint on smeared plaster. 
 
 The collection of evidence was convincing enough for El Damaty to approve infrared thermography of part of the north wall in early November 2015. The imaging technique detects variations in surface temperatures, which presumably would be different for a solid limestone wall and one concealing a room, if there was one. The imaging revealed tantalizing temperature differences on the north wall. 
 
 Later that month, Japanese radar specialist Hirokatsu Watanabe used GPR to peer behind the tomb walls. The results were sensational and made headlines around the world. Watanabe thought he could see chambers behind the north and west walls, as well as artifacts of metal and organic materials. 
 
 But many Egyptologists and GPR experts had serious doubts about the results of that survey, so a second round of GPR was launched in March 2016. This time National Geographic engineers carried out the work. 
 
 Expectations were huge, but the results were puzzling. The survey was designed to look for walls of the same thickness that Watanabe had seen, but it didn’t pick up anything like that—or any hint of voids to the north or west of Tut’s burial chamber. 
 
 The results of those two probes brought the investigation to a standstill. The project needed a tiebreaker. 
 
 Results: Yes or No? 
 
 The third GPR survey will leave no stone unturned by radar technology, with plans calling for several four-hour sessions of scanning. The results of the completed work should hopefully provide the final answer on whether there are hidden chambers or not. Scientists caution, however, that the GPR scans can only detect “anomalies” in the rock, and further research will be required to determine if any anomalies are in fact hidden rooms. 
 
 The current project, a joint scientific mission between Egypt and Italy, is being coordinated by Italian physicist Francesco Porcelli from the Polytechnic University of Turin in partnership with the University of Turin and three private companies, Geostudi Astier, 3DGeoimaging, and Terravision. 
 
 “I'm privileged to be given this opportunity, and I'm privileged to be coordinating such a great team,” Porcelli told National Geographic during a break between scanning sessions on Thursday evening. 
 
 The GPR team works through the night, after the Valley of the Kings and Tut's tomb are closed to tourists. The researchers carefully navigate their high-tech equipment in the tight spaces of the burial chamber under of the supervision of Egyptian officials, careful to ensure that the radar antennas scan as close as possible to the wall surfaces without disturbing the priceless paintings of the 3,300-year-old tomb.
– The theory that King Tut's tomb also holds the remains of his stepmother, the legendary Queen Nefertiti, has tantalized Egyptian archaeology for nearly three years. But after two scans with ground-penetrating radar proved inconclusive, National Geographic reports that third major scan is underway at the tomb in Luxor's Valley of the Kings, and it has exclusive photos of the operation. The scan will search the walls of Tut's tomb for signs of a hidden chamber and is expected to take about a week, reports CBS News. Several weeks of analysis will then follow. Egyptologist Nicholas Reeves believed he saw telltale signs—traces of sealed entrances in the north and west walls of Tut's tomb—in a 2015 scan. It's also been determined that the north wall was initially painted a different color than the others, while paintings on the wall also follow a different pattern than those on the others. This might suggest the wall—where infrared thermography found temperature variations—was built some time before the others. But though experts said a 2015 scan indicated chambers present behind the north and west walls, a second scan in 2016 found nothing. The third scan, being led by the Polytechnic University of Turin, aims to settle whether any voids in the rock exist. If so, archaeologists would then begin the next phase of seeing what's inside them. (Tut's dagger is out of this world, literally.)