Eleven Thousand Years Underground

A hilltop in southeastern Turkey where people who had no pottery, no farming, and no wheel quarried and raised carved limestone pillars around 9600 BCE. A survey team reached it in 1963, wrote it up as a medieval cemetery, and moved on.

Start at Göbekli Tepe, whose carved megaliths predate Stonehenge by roughly 6,000 years. The German Archaeological Institute's excavators long held that the builders buried the rings on purpose. They now read the fill as debris from repeated slides off the slopes above.

In 1963, a resident renovating a house found a passage behind a wall that led into a complex descending roughly 85 meters across eight levels. Byzantine Christians expanded it as a refuge during the Arab-Byzantine wars, and it is estimated to have sheltered up to 20,000 people.

Drive northwest into Cappadocia to Derinkuyu, an underground city carved to shelter thousands of people and their livestock, sealed behind rolling stone doors and rediscovered only in 1963. Derinkuyu runs as a ticketed museum open every day, and about 10 percent of the complex is open to visitors.