An engineering puzzle underground
The Serapeum of Saqqara is a subterranean complex carved directly from the limestone bedrock. It consists of a network of tunnels, with the main gallery stretching for hundreds of meters. Housed within rock-cut chambers along these corridors are 24 enormous sarcophagi. Each was carved from a single block of hard stone, usually rose or black granite, with some made of diorite or limestone.
The immense size and weight of these objects present a significant engineering question. The sarcophagi bodies alone weigh up to 40 tonnes (88,000 lb), with their massive lids adding another 25 to 30 tonnes. One of the largest examples has external dimensions of 3.85 meters long, 2.32 meters wide, and 2.32 meters tall. The total weight of some of these sarcophagi is estimated to be between 60 and 80 tons. Maneuvering these monoliths through the narrow underground passages and lowering them into their alcoves was a formidable task. Remnants of winches and rollers found at the site suggest the methods used, and one ancient record states that it took 28 days to move a single sarcophagus into its chamber around the year 247 BCE. The precision of the boxes is significant; many feature perfectly flat interior and exterior surfaces polished to a mirror finish, with sharp, true corners.
The cult of the Apis bull
The Serapeum was the burial place for the sacred Apis bulls for approximately 1,400 years, from the New Kingdom (beginning around 1400 BCE) until the Roman period. In ancient Egyptian religion, the Apis bull was considered a manifestation of the creator god Ptah. Upon death, the bull was associated with Osiris, the god of the underworld, becoming Osiris-Apis, or "Serapis" in the later Hellenistic period.
A new Apis bull was selected by priests based on a very specific set of markings. These included a black coat, a white diamond-shaped mark on its forehead, the image of an eagle on its back, a scarab-shaped lump under its tongue, and double the number of hairs on its tail. Once identified, the sacred animal lived a life of luxury in the temple at Memphis. When the bull died, it was mummified in a lavish 70-day ritual and interred with full honors inside one of the granite sarcophagi in the Saqqara necropolis.
The site was rediscovered in 1850 by French archaeologist Auguste Mariette. He had been guided by the writings of the ancient Greek geographer Strabo, who described an avenue of sphinxes leading to the temple. Mariette uncovered this avenue and, on November 12, 1851, used explosives to clear the blocked entrance and enter the catacombs for the first time. Inside, he found that all but one of the sarcophagi had been plundered in antiquity.