What is the largest city on the Caspian Sea and of the Caucasus region, has a railway line in the station in a settlement in the municipality of Nakhchivan in Nakhchivan City, Nakhchivan Autonomous Republic, Azerbaijan?
Baku: Baku ( , ; Azerbaijani: "Bakı" , ] ) is the capital and largest city of Azerbaijan, as well as the largest city on the Caspian Sea and of the Caucasus region.
i don't know