The city in southeastern Turkey resounds with music, food and culture — and echoes with more than 11,000 years of human history.As we climbed the slope toward one of the world’s most momentous archaeological sites in a gusty December drizzle, a futuristic shape loomed into view. It was the swooping white canopy erected over the main excavation at Gobekli Tepe, a group of Neolithic structures up to 11,400 years old in southeastern Turkey. Their unearthing in the mid-1990s caused a…