Istanbul is one of the great cities on earth—period. For thousands of years, this place, where East meets West, has been a crossroads of civilizations. And for over 400 years it was the capital of the Ottoman Empire…and those sultans left quite a heritage.

We’ll see the historic highlights of this city: explore an Ottoman palace, marvel at the sultans’ treasures, be dazzled by Byzantine domes, anticipate with the Ramadan faithful the call to prayer, and descend into an ancient Roman cistern. We’ll go local in a sea of locals: sort through exotic spices, dine fine with the help of the local firewater, survive a flaming face shave…and then luxuriate in an Ottoman bath.

Turkey bridges Europe and Asia. Istanbul, its largest city, straddles the Bosphorus Strait. Part of the city’s in Europe, and part in Asia. The Golden Horn inlet, long a strategic harbor, is crossed by the Galata Bridge, which connects the bustling New Town and the Old Town, which fills a peninsula conveniently protected by a mighty wall. Here we’ll find the venerable sights of the sultans: the ancient Hagia Sophia, the Blue Mosque, and the fabled Topkapı Palace.

While today the city is a vast megapolis of over 15 million people sprawling along both sides of the Bosphorus, its oldest citizens actually remember when it had only a million people. In other words, most of the city is new, and its historic points of interest are mostly corralled into a compact old center.

It’s easy to overlook that in the year 600, Istanbul—with half a million people—was the largest city in all of Europe.

One good way to fathom that is to descend into one of its massive cisterns—as the ancient city had an impressive water system. This cistern was built 1,500 years ago by Emperor Justinian, who built many of the city’s grandest buildings. Some of these columns were scavenged from ancient temples…giving the cistern a few artistic surprises.

It was a huge underground reservoir, one of many that brought water to the city’s residents. This one was the biggest, as it served the emperor’s palace.

For nearly a thousand years, fresh water from 10 miles away was channeled here through pipes and across aqueducts.