That point is near the western coast of the southern Caspian Sea,
about 44 km south of Baku, Azerbaijan.
Sea of Japan.
The Caspian Sea
40 degrees n, 50 degrees e is actually a sea. It is the Caspian Sea.
Bohai Sea.
The Mediterranean Sea.
Mediteranean sea
It is the Tyrrhenian Sea.
There is no river at 30 degrees north and 40 degrees east.
It is the parrnell's strait
Antarctica is located 0 degrees north and 40 degrees east.
The coordinates 40 degrees north and 100 degrees east correspond to Asia.
The country at 40 degrees north latitude and 40 degrees east longitude is Turkey, specifically the city of Sivas in central Turkey.