Cultural Answer
Beauty is in the eye of a beholder though?
Who sees european and asian characteristics of Turkey as a separating aspect?
For Turkish people there is no separation but unification of unique character; being both Asian and European, western and eastern in one entity.
So, may be you have to check where do you see separation to your eyes.
Geographic Answer
European and Asian Turkey are separated by three bodies of water, from north to south:
Bosporus Strait which starts at the Black Sea on Turkey's northern coast and then runs down through Istanbul at its southern end (separating neighborhoods like Sultanahmet and Beyoğlu on the European side from Üsküdar).
Sea of Marmara which is a small sea between Istanbul and the Gallipoli Peninsula. The island of Marmara in the sea was used by Romans as a marble quarry. Since Marmara is the Latin word for marble, the term was applied to island and the sea in general. Europe is to the north and west of the Sea of Marmara and Asia is to south and west.
Dardanelles Strait which starts at the Sea of Marmara as it narrows between Anatolia and the Gallipoli Peninsula and then runs down to the city of Çanakkale on the Aegean Sea.
Dardanelles Strait
Istanbul, Turkey is a city that straddles two continents: Europe and Asia. The Bosphorus Strait separates the European and Asian sides of the city.
The Bosphorus Strait in Turkey is a natural landform that joins the continents of Europe and Asia. It separates the European part of Istanbul from its Asian counterpart.
The water passageway that leads to the Black Sea through Turkey is the Bosporus or Istanbul Strait. It separates the European part of Turkey from the Asian part.
The Bosporus (or Bosphorus) is a strait, a narrow passage of water between two large landmasses, that separates the European section of Turkey from the Asian section. See the link for more details.
"Hellespont" is the ancient name for the Dardanelles, which is a strait that separates Asian Turkey from the Gallipoli peninsula of European Turkey, and links the Aegean Sea with the Sea of Marmara.
Black Sea
Istanbul, Turkey is a city that spans the two continents of Asia and Europe. The Bosphorus Strait separates the European and Asian sides of the city.
the bosporus straights are in turkey
The two continents that the Constantinople was located was Asia and Europe.
I believe that is the Strait of Hormuz going into the Gulf of Oman.
The Bosporus/Bosphorus Strait is in northwest Turkey. It connects the Black Sea with the Sea of Marmara. This is the northernmost part of the Turkish Straits.