Gobekli Tepe is known as the oldest temple site on the Earth. It consists of several man made mounds covering and ancient temple complex that is multiple football fields in size. Multi-ton stone pillars with detailed carvings held up the central chambers of these temples. Yet for all it's majesty there is a controversy surrounding Gobekli Tepe. 
Gobekli Tepe was created at least three thousand years before the alleged dawn of civilization by people that mainstream scientists simply label hunter gatherers. This site begs for us to reconsider our understanding of technological and cultural progression across human history and is the center point of many conspiracy theories attempting to explain it's existence.