Is there any other fact about North Sea I may be interested in? 
 interesting.. What happened after that? 
 Wow. I have no idea of that. What can you tell me about the geology? 
 Hey there! I would like to know about North Sea please? 
 Submarine warfare was used extensively in the North Sea during the first World War. This was the first time Submarine Warfare was used.
Submarine warfare was used extensively in the North Sea during the first World War. This was the first time Submarine Warfare was used.