Below a 2,300-year-old pyramid are three chambers and a tunnel, where the preserved sarcophagus of a pharaoh remains hidden. They remained almost inaccessible, until a team of archaeologists explored it, due to being filled with water.

Unlike the Egyptian pyramids that supposedly served as tombs and where the pharaohs were 'buried' inside the monuments, Sudan's pyramids have a key difference: the pharaohs' tombs were placed below the structure, rather than inside them. And it is beneath these 'forgotten pyramids' that a group of archaeologists exploring Sudan's hot desert have made a discoveryastonishing

Thousands of years ago, the land of Nubia was home to the Black Pharaohs and a collection of ancient pyramids that, while not as large as the Egyptian ones, are equally fascinating. Some of these pyramids have been at least partially explored by archaeologists for several decades. One of these pyramids, belonging to Nastasen, was explored about a century ago. It was forgotten and buriedthrough the sands.

The archaeologists, packed with diving equipment and their indispensable archaeological instruments, wanted to take a look inside the ancient pharaoh's tombs. The mission was difficult.

To reach the tombs, archaeologists had to overcome a number of obstacles. The biggest one was water: to access the passages and chambers below the pyramid, researchers had to dive into the muddy water.

Fortunately for them, the tomb they were now exploring had already been raided by George Reisner, a Harvard Egyptologist who had visited Nuri a century ago.

It was thanks to Reisner's work that archaeologists knew that many of the tombs were filled with water, making traditional archaeological excavations an impossible task.

Reisner and his team excavated the pyramid of Nastasen briefly. According to his notes, one of his team members entered the tomb on his way to the final chamber. There, he managed to dig a small space in the corner, eventually collecting small figurines to be used in the pharaoh's afterlife. The items were collected, and Reisner and his team left. The tomb was finallyforgotten, until recently, when National Geographic archaeologist Pearce Paul Creasman decided to follow in Reisner's footsteps, and enter the tomb.

It was precisely in the pyramid belonging to Nastasen, and after accessing a submerged tunnel and three water-filled chambers, that underwater archaeologists discovered a number of artifacts inside the submerged tomb of a pharaoh named Nastasen, ruler of Nubia and the Kush Kingdom, circa 335 B.C.E. to 315 B.C.E.

After making it through a staircase leading to Nastasen's tomb, the archaeologists found a water table. To go further, they needed to put on their diving equipment and work up some underwater archaeology.

Packed with oxygen tanks and archaeological tools, they wanted to see what the tomb looked like. Image Credit: National Geographic

The water levels were high and were the result of what experts described as "increased groundwater caused by natural and human-induced climate change, intensive agriculture near the site, and the construction of modern dams along the Nile."

However, scientists entered the tomb, eventually emerging with fragments of gold leaf that once covered figures inside the ancient tomb.

The third and final chamber below the pyramid is where experts believe Pharaoh is buried.

Creasman and Romey accessed the chamber in their scuba gear and floated just above the 2,300-year-old Nastasen sarcophagus undisturbed.

Now, packed with experience, and knowing what to expect, their goal is to return to the site in 2020 and attempt to excavate the burial chamber, which they themselves argue is an audacious and logistical challenge.

SOURCE/READ MORE : Dive beneath the pyramids of Egypt's black pharaohs [National Geographic]