  The Great Pyramid or Khufu's Pyramid was built on the Giza Plateau (Egypt)
during the IVth dynasty by the pharaoh Khufu (Cheops), who reigned from 2509 to
2483 BC. Despite being one of the oldest and largest monuments on Earth, there
is no consensus about how it was built. To better understand its internal
structure, we imaged the pyramid using muons, which are by-products of cosmic
rays that are only partially absorbed by stone. The resulting cosmic-ray muon
radiography allows us to visualize the known and potentially unknown voids in
the pyramid in a non-invasive way. Here we report the discovery of a large void
(with a cross section similar to the Grand Gallery and a length of 30 m
minimum) above the Grand Gallery, which constitutes the first major inner
structure found in the Great Pyramid since the 19th century. This void, named
ScanPyramids Big Void, was first observed with nuclear emulsion films installed
in the Queen's chamber (University of Nagoya), then confirmed with scintillator
hodoscopes set up in the same chamber (KEK) and re-confirmed with gas detectors
outside of the pyramid (CEA). This large void has therefore been detected with
a high confidence by three different muon detection technologies and three
independent analyses. These results constitute a breakthrough for the
understanding of Khufu's Pyramid and its internal structure. While there is
currently no information about the role of this void, these findings show how
modern particle physics can shed new light on the world's archaeological
heritage.
