The barren, rocky hill takes the form of a would-be mesa piled with and shaped by dozens of rock stacks. Its cavern was made into a small necropolis for the people of Siwa in ancient times, hence its name.
The tomb itself contains multiple burial chambers—one of which served as a repository for cats. Its most notable room, however, is its central chamber that holds a giant sarcophagus several feet deep on one end opposite a great, metal gate. Set before this sarcophagus is a stele dating back to the Old Kingdom with writing of that period in Egypt inscribed upon it.
A smaller cave, disconnected from the main tomb, was set aside for the burial of the local Medjay and their kin. In contrast to its greater counterpart, this lacked ornamentation and is largely plain, with bare recesses lining the walls to serve as the resting places of mummies—all without sarcophagi or any other container—in a manner similar to that of Roman catacombs. The exception is the burial room to Khemu, the son of the Medjay Bayek, which holds a great alabaster coffin set into an alcove and decorated with red hand prints. On either side were hundreds of wax candles placed on top of stone tables carved from the walls.
As far back as the Old Kingdom, the hill served as the tomb for the people of the remote village of Siwa in Egypt, earning its name as the Mountain of the Dead. Esteemed individuals from Siwa were buried there, including Minhotep, his wife Agathoclea, and their son Teti. In accordance with Egyptian culture, cats, such as the honored Tai Miuwette, were also mummified and laid inside.
In 48 BCE, Bayek returned to Siwa after a year abroad hunting Rudjek, one of the Order of the Ancients responsible for the death of his son. When he visited the Medjay tomb, he found that in his absence and with the installation of Medunamun as the new Oracle of Siwa, upkeep for it had ceased and much of it was covered in cobwebs. Much of it was ransacked by animals which had used it as their den while he was away whereas in previous years Bayek and the villagers constantly kept it pristine to respect his ancestors.
Shortly after Bayek's return, the child Chenzira brought his brother Fenuku to visit a hyena den on the side of the hill, hoping to catch sight of their skulls. When the hyenas suddenly returned before they left, the pair fled in opposite directions, with Chenzira running into the main tomb itself. Fenuku was chanced upon by Bayek and told the Medjay of his brother's predicament, prompting Bayek to enter the tomb to find Chenzira. In short order, he was able to locate him in the central chamber, where, before escorting the boy out, he deciphered the secrets inscribed on its Old Kingdom stele.
A year later in 47 BCE, Bayek's friend and fellow Medjay Hepzefa was murdered by Flavius and Lucius Septimius in the Siwa vault beneath the Temple of Amun. Bayek carried his body to the tomb, where he was mummified and mourned by the villagers of Siwa.