Gisr el-Mudir

Gisr el-Mudir, (Arabic for "enclosure of the boss") located at Saqqara in Egypt, just west of Sekhemkhet's pyramid complex, is a massive enclosure that seems to date from the Second dynasty. The structure was located in the early Twentieth century, but not investigated until the mid-1990s, when it was found to be masonry of roughly hewn limestone blocks in layers, making it the earliest known stone structure in Egypt

http://egyptphoto.ncf.ca/Gisr%20el-mudir.htm