Sea of Marmara
The Sea of Marmara (Turkish: Marmara Denizi, Greek: Θάλασσα του Μαρμαρά), also known as the Sea of Marmora or the Marmara Sea, and in the context of classical antiquity as the Propontis (Greek: Προποντίς), is the inland sea, entirely within the borders of Turkey, that connects the Black Sea to the Aegean Sea, thus separating Turkey's Asian and European parts. The Bosphorus strait connects it to the Black Sea and the Dardanelles strait to the Aegean. The former also separates Istanbul into its Asian and European sides.
Open Water Swimming
Mercedes Gleitze swam here in 1930.