The Buried Pyramid was a previously unknown structure until, in 1951, Egyptologist Zakaria Goneim noticed the odd rectangular shape in the desert while excavating the nearby Unas complex.
A three part rubble-coursed enclosure wall was first discovered, and by digging to its bottom, it was found to be 5.2 m (17 ft) tall and 18 m (60 ft) thick.
He later discovered that the wall further extended on both sides to dimensions of 520 m (1,700 ft) in the north-south axis and 180 m (600 ft) to the east-west and was full of false doors and niches.

The pyramid itself was located at the centre of the complex, with a base length of 115 m (377 ft), it had only one step and was unfinished.
During the next stage of excavation, Goneim discovered a descending passage to the north side which led to a gallery blocked with rubble and masonry.
There were a number of objects found during the excavation of this gallery including animal bones, demotic papyri, and Third Dynasty stone vessels.
In a decayed wooden casket, gold was discovered which included gold bracelets, cosmetic cases, beads, and jars inscribed with Sekhemkhet's name.

When the blocked wall was breached, on May 31, 1954, an unfinished and undecorated burial chamber was discovered.
Inside it, lay an alabaster sarcophagus cut from a single block with a vertical lid which seemed to still be sealed.
However, on June 26, 1954, after great difficulties to unblock and raise the lid, the sarcophagus was opened and to everyone's disappointment, it was empty.

Criticism of Goneim and his subsequent suicide on January 12, 1959 dampened the interest in the pyramid and investigation was left incomplete.

In 1963, the excavation was re-opened by Jean-Philippe Lauer due to the possibility of a south tomb and his desire to find the missing mummy.
Lauer did indeed find a partially destroyed tomb under the southern side that at some point had been looted by robbers.
 He found a wooden coffin with the remains of an unidentified two-year-old child and gold leaf fragments.
The Buried Pyramid was a previously unknown structure until, in 1951, Egyptologist Zakaria Goneim noticed the odd rectangular shape in the desert while excavating the nearby Unas complex. A three part rubble-coursed enclosure wall was first discovered, and by digging to its bottom, it was found to be 5.2 m (17 ft) tall and 18 m (60 ft) thick. He later discovered that the wall further extended on both sides to dimensions of 520 m (1,700 ft) in the north-south axis and 180 m (600 ft) to the east-west and was full of false doors and niches.
The pyramid itself was located at the centre of the complex, with a base length of 115 m (377 ft), it had only one step and was unfinished. During the next stage of excavation, Goneim discovered a descending passage to the north side which led to a gallery blocked with rubble and masonry. There were a number of objects found during the excavation of this gallery including animal bones, demotic papyri, and Third Dynasty stone vessels. In a decayed wooden casket, gold was discovered which included gold bracelets, cosmetic cases, beads, and jars inscribed with Sekhemkhet's name.
When the blocked wall was breached, on May 31, 1954, an unfinished and undecorated burial chamber was discovered. Inside it, lay an alabaster sarcophagus cut from a single block with a vertical lid which seemed to still be sealed. However, on June 26, 1954, after great difficulties to unblock and raise the lid, the sarcophagus was opened and to everyone's disappointment, it was empty.
Criticism of Goneim and his subsequent suicide on January 12, 1959 dampened the interest in the pyramid and investigation was left incomplete.
In 1963, the excavation was re-opened by Jean-Philippe Lauer due to the possibility of a south tomb and his desire to find the missing mummy. Lauer did indeed find a partially destroyed tomb under the southern side that at some point had been looted by robbers.  He found a wooden coffin with the remains of an unidentified two-year-old child and gold leaf fragments.
Buried Pyramid