List of Waterways you can go through & tips

Name of Waterway..................Location................................How to block it (100+)......................................Importance

Panama Canal.........................Panama.................................Capture Panama city.........................................Fastest route from Pacific to Atlantic
Suez Canal.............................Egypt...................................Build a wall on it (Capture Port Said or Suez)..........Attaches the Mediterranean Sea to the Indian Ocean
Strait of Hormuz/Gulf of Oman....Iran/United Arab Emirates.........Build a wall from UAE to Iran...............................Fastest way from Middle East to Indian Ocean
Gibraltar.................................Spain/Morocco.......................Build a wall from Spain to Morocco.......................Links Atlantic Ocean with Mediterranean Sea
Kattegat/Skagerrak..................Norway/Sweden/Denmark.........Build wall from Denmark to Norway/Sweden............Links Baltic Sea to Atlantic
Bosphorus..............................Turkey..................................Capture Istanbul...............................................Links Black Sea to Sea of Marmara/Mediterranean
Marajo Bay.............................Brazil: Northeast.....................Build wall.........................................................Flows to Belem
Gulf of St. Lawrence................Canada: Quebec.....................Build Wall.........................................................Flows to Quebec City
Singapore Straight...................Singapore/Indonesia/Malaysia....Build wall from Malaysia to Indonesia....................Fastest way from India to Indonesia/Australia
Arabian Straight......................Oman/Djibouti.........................Build wall from Oman to Djibouti..........................Links Red Sea to Arabian Sea

Use the Table bb code next time. Some errors, but pretty good thread.