Great Ziggurat of Ur
On a dead-flat alluvial plain with no stone, no timber and no mountain for hundreds of kilometres, how did Sumerian builders raise a thirty-metre artificial peak out of nothing but mud, reeds and tar — and engineer it so cleverly that its lowest stage is still standing, and still load-bearing, four thousand years later?
c. 2100–2050 BCE (Third Dynasty of Ur — begun by Ur-Nammu, completed by Shulgi) · Ur, near Nasiriyah, Dhi Qar Governorate, IraqAdded September 2026