Based on the world record nomination from Europe Records Institute (EURI) and Decision No. WK/USA.INDIA/686/2021/No.142, World Records Union (WorldKings) officially declared Bosphorus is the world's narrowest strait on April 27, 2021.
Bosporus is a strait separating the European part (Rumelia) of Turkey from the Asian part (Anatolia) of this country. It is the strait used for international navigation, the Bosporus connects the Black Sea with the Sea of Marmara, and, by extension via the Dardanelles, the Aegean and Mediterranean seas.
The Bosporus is 30 km long, with a maximum width of 3.7 km at the north entrance and a minimum width of 0.75 km between the fortresses Anadoluhisari and Rumelihisari. Depth ranged from 36 to 124 meters in the middle of the flow.
Most of the shores of the strait, except for those in the north, are heavily settled, straddled by the city of Istanbul's metropolitan population of 17 million inhabitants extending inland from both coasts. Together with the Dardanelles, the Bosporus forms the Turkish Straits.
The Bosphorus is the only way for Bulgaria, Georgia, Romania, Russia (South-Western part) and Ukraine to reach the Mediterranean Sea and other seas. Although it is only one of the natural borders separating the European and Asian mainland, the most known is the Bosphorus. Since it is a favorable region in terms of climate and geographical conditions, it has had a great role in being a settlement area for ages.
According to Wikipedia