ANKARA   -  Turkey is rich with ancient wonders. Straddling Europe and Asia, the country has been at the heart of numerous empires, which have left behind archaeological attractions to rival its many natural wonders. But not everything sits above ground, basking in Turkish sunshine. Less obviously visible but equally impressive are the historical treasures, some more than 12,000 years old, that can be found underground. Some are well known. Istanbul’s Basilica Cistern, a columned reservoir that dates back to Roman times, has been open to tourists for decades and featured in movies including the James Bond classic “From Russia with Love.” Others may not be as famous, but are no less spectacular or fascinating. Like the Basilica, this elegant cistern was built during late Roman times to ensure a supply of water to Constantinople, as Istanbul was once known. Unlike the Basilica, this underground chamber was completely forgotten about until less than 15 years ago. The Şerefiye Cistern, was constructed during the reign of Theodosius II, ruler of the Eastern Roman - or Byzantine - Empire from 402 to 450 CE in what is now Istanbul’s Fatih district. It was constructed to store fresh water brought from Belgrade Forest, a wilderness near the Black Sea north of the city, via a 155-mile-long canal network that included the ancient Aqueduct of Valens, which still stands in Fatih. The water was then distributed to citizens. At 82 by 147 feet (25 by 45 meters), with a ceiling almost 36 feet high, walls eight feet thick and 32 marble columns, the structure also known as the Theodosius Cistern – is as substantial as it is beautiful.