A mastaba is the superstructure over an ancient Egyptian tomb, the tomb chamber being deep underground. At first no more than a low rectangular bench-like structure of mudbrick, mastabas later became more imposing, sometimes partly stone-built. Dynasty I and II mastabas survive at Saqqara and Gizeh outside Cairo. Pyramids developed from mastabas, e.g., the step-pyramid at Saqqara (c. 2700 BC) which is a mastaba enlarged by adding units of decreasing size.