The first picture: St. Lawrence River, ob river, Rhine+Danube (Rhine-Danube Canal), Lena River, Nile River (White Nile), Suez Canal, Volga River, Liaohe River, ...

The second picture: North Sea, Gulf of Mexico, mozambique channel, Aegean Sea, Caribbean Sea, strait of magellan, Mediterranean Sea, Korean Strait, Sea of Japan, Gulf of Aden, Persian Gulf and Gibraltar Strait.

The third picture: Rhine River, Balkhash Lake, ... (No bad judgment on longitude), Loire River, Kiel Canal, Chao Phraya River, Lake Superior, parana river, Ganges River.