A Narrow Waterway Between Seas
A strait is a narrow channel of water that links two larger bodies of water. One of the most famous and important straits in the world is the Bosphorus. It is a narrow waterway in Turkey that connects two seas: the Black Sea and the Sea of Marmara. Though narrow, it is one of the most significant waterways on the planet.
Running Through a Great City
What makes the Bosphorus especially remarkable is that it runs directly through the middle of a major city, Istanbul. This means Istanbul sits on two continents at once. The land on one side of the strait is part of Europe, and the land on the other side is part of Asia. The Bosphorus is one of the natural dividing lines between these two continents, and bridges across it physically connect Europe and Asia.
A Chain of Connected Waters
The Bosphorus is one link in a longer chain of waterways. On its northern end, it opens into the Black Sea, a large sea bordered by several countries. On its southern end, it leads into the smaller Sea of Marmara. From there, another strait, the Dardanelles, continues the route onward toward the Aegean Sea and then the wider Mediterranean. So the Bosphorus is a vital part of the only sea route connecting the Black Sea to the world's oceans.
Why the Bosphorus Matters
Because it is the gateway between the Black Sea and the rest of the world, the Bosphorus has been strategically important for thousands of years. Countless ships pass through it, carrying goods between many nations. Its control has been valued and contested throughout history. Today it remains one of the busiest and most important shipping passages anywhere, a narrow ribbon of water with global significance.
Source
This article was written using information from Wikipedia.