Pyramid of Senusret I

29.5667°N, 31.2167°E.

Twelfth-Dynasty pyramid at el-Lisht, immediately south of the pyramid of Amenemhat I, built for pharaoh Senusret I, who reigned approximately 1971–1926 BCE. Original base 105 metres per side; original height 61 metres at a 49° slope — the largest pyramid built since the late Fifth Dynasty. Excavated by Joseph Gautier and Gustave Jéquier from 1894, then continued by the Metropolitan Museum's mission from 1906. The internal structure uses a distinctive radial framework of eight limestone walls running diagonally from the centre to the corners and the midpoints of each face, with the spaces between filled with rough-cut stone — a technique never used before or after. Nine satellite queen's pyramids were arranged around the main pyramid, one of the largest such complexes of the Middle Kingdom. The mortuary temple yielded two seated cedar statues of the king, ten limestone Osiride statues, and a sphinx avenue connecting to the valley temple.

A king who built bigger than any pharaoh of the previous five centuries, with an internal armature so unusual it has been used to identify reused blocks elsewhere in the country.