Mystery is no stranger to the Great Pyramid of Giza. For centuries, scientists and archaeologists have probed inside the largest and oldest of Egypt's famed pyramids that is featured on the back of the $1 dollar bill. But, until now nobody had stumbled upon the long space hidden within its limestone and granite walls. An international group of scientists has used modern technology to visualize the inside of the pyramid, according to an article by National Geographic. But what or who, is hiding in the newly discovered mystery void within the Great Pyramid of Giza? Could it be aliens?

The purpose of the black hole void within the Great Pyramid of Giza is unclear, and it's not yet known whether it was built with a function in mind or if it's merely a gap in the pyramid's architecture. Some experts say such empty spaces have been known for years. Mehdi Tayoubi, a co-founder of the pyramids project and president of the Heritage Innovation Preservation Institute said, "It could be composed of one or several structures... maybe it could be another Grand Gallery. It could be a chamber; it could be a lot of things."

The 4,500-year old pyramid was built during the reign of Khufu or Cheops, the second pharaoh of the Fourth Dynasty of the Old Kingdom of ancient Egypt. Despite being one of the oldest and largest monuments on Earth, there is still no consensus about how the Great Pyramids were built. To better understand its internal structure, researchers imaged the pyramid using muons, which are by-products of cosmic rays that are only partially absorbed by stone.

The news comes after a giant hole the size of Lake Superior opened up in Antarctica. Scientists cannot explain why the mystery hole has appeared again after 40-years, but they have better technology to study it this time around. The spot was first observed in the same exact location in the 1970s, which was when the first satellites were launched that provided images of the sea ice cover from space. It reportedly looks like someone, or thing, simply punched a hole in the ice. Many speculate that aliens have hidden their ship in that massive hole, just waiting for the perfect time to come out and the same may be the case inside the Great Pyramid as well.

Nobody can explain how the pyramids were built and researchers aren't certain what they'll find when they attempt to look inside the Great Pyramid of Giza and its newly discovered mystery void. When there aren't any clear explanations, aliens may be the best bet. It was also recently reported that aliens may look like humans due to biological evolution in our solar system, which also adds to the mystery of the Great Pyramids and how they were constructed. Human-looking aliens might have built it and they might be coming back to retrieve what they left behind. You can read more about the new discovery via The National Geographic.