El Lahun Pyramid is located in Fayoum, it was built by king Senusret II, of the Twelfth Dynasty, who ruled during the period between 1975-1640 B.C, and discovered by Lepsius expedition.
The pyramid of Senusret II in Lahun was built on a high hill that is 13 meters high and it was constructed out of mud bricks. The pyramid is 48 meters high and the length of its base is 106 meters, it was coated of limestone.
The pyramid core is composed of cross walls of limestone over knoll of rock ,and its entrance was built in the southern side, and unlike all the other pyramids of Egypt, the entrance leads to a number of complicated corridors that surround the burial room in a unique design in order to trick thieves.
Some ruins of the mortuary temple of the pyramid are still remaining to the east of the pyramid. There are also some small pyramids that belong to the queens and princess of the royal family of Senusret II.
The area hosts a number of other sites like the necropolis of Lahun, and the Tomb of Mkat that goes back to the 13th dynasty.
The Lahun Pyramid was opened by the English scientist William Flinders Petrie in 1889, and found inside it a golden cobra, which was put on the royal crown, transferred then to the Egyptian Museum in Cairo, moreover, the tomb of Princess Sat Hathor was also discovered next to the pyramid.