Big discovery at the pyramids

'Big void' identified in Khufu's Great Pyramid at Giza

http://www.bbc.com/news/science-environment-41845445

It is not known why the cavity exists or indeed if it holds anything of value because it is not obviously accessible.
Japanese and French scientists made the announcement after two years of study at the famous pyramid complex.
They have been using a technique called muography, which can sense density changes inside large rock structures........................