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. Few places on Earth have witnessed more history than this sprawling metropolis on the Bosphorus.

Turkey bridges Europe and Asia. Its largest city, Istanbul, 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. It connects the bustling New Town and the Old Town with its fabled palace and mosques. After a cruise on the Bosphorus, we’ll explore the Grand Bazaar, wander down the İstiklal Caddesi boulevard, then finish in Asia with a visit to Üsküdar.

Inspiring monuments showcase 2,000 years of Istanbul history: its ancient Roman and early Christian Byzantine period, its centuries as the capital of the Muslim Ottoman Empire, and its birth as a modern nation in the 20th century. 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, the vast majority of the city is new. And its historic points of interest are mostly corralled into a relatively compact old center.

The starting point for many travelers is Istanbul’s state-of-the-art cruise terminal—with its ingenious collapsible walls. It adds to the city’s population whenever ships are in port. A farsighted infrastructure investment, all the buses and taxis are underground to efficiently move the crowds. In season, massive cruise ships pour thousands of tourists smoothly into the city for a busy day of sightseeing and shopping.

When ships sail, the security and customs walls fold down, and Galataport transforms into a delightful public promenade—600 yards long. Late in the day, the people watching mixes with the commotion of the busy harbor to make it a Turkish paseo like none other.

The Bosphorus is churning with boat traffic of all sorts. This narrow and strategic strait is a bottleneck busy with freighters, including lots of Ukrainian and Russian ships, since this is the only route between ports on the Black Sea and the Mediterranean. And tourist boats, doing their maritime do-si-do, dance around the serious cargo ships and ferries.

For more of a mini-cruise, it’s easy to hop a sightseeing boat for a relaxing sail up the Bosphorus.

Yes, an intercontinental cruise. It’s a chance to see Istanbul from the water and get the lay of the land, with Europe on one side and Asia on the other.

Small, historic towns, marked by their minarets, are now engulfed in the sprawl of modern Istanbul. The boat passes an Ottoman emperor’s hunting lodge, palaces of the nobility, and homes of wealthy locals—locals who can afford Bosphorus waterfront, some of the priciest real estate in all of Turkey. And anyone can enjoy the inviting beachfront parks. The dramatic Bosphorus Bridge was the first bridge ever to span two continents. And the Rumeli Fortress was built by the Ottomans five centuries ago.

Back in the old center, the Galata Bridge spans the strategic inlet called the Golden Horn. For centuries this easy-to-defend bay provided the city a protected harbor.

A thousand years ago, long before there was a bridge here, a mighty chain was stretched across the mouth of this inlet. This gave the Byzantine Empire its safest harbor, which provided the city a critical key to both trade and military power.

While just a few years ago its shoreline was an industrial wasteland, today the Golden Horn is cleaned up and lined by inviting parks. After a determined effort by the city and lots of investment, the people of Istanbul now share a delightfully green and welcoming people zone: the Golden Horn.

Back at the Galata Bridge, for fast food Istanbul-style, you can grab a fish-wich just off the boat—mackerel, fresh from the guys who caught it, at one of the venerable, and very tipsy, fish-and-bread boats.

And as the sun sets, on the bridge you can enjoy panoramic views of Istanbul’s Old Town, an iconic place for more fast fish, or a nice dinner with a view of the harbor action. There are lots of tourists in Istanbul. And it’s interesting to note that about half of them come from other Muslim countries.