Most Impressive Naval Vessels of WWI

[Scarecrow]

What Naval Vessels were the most impressive of WWI?
I do not have a name for one, but I would imagine a German U-Boat would be at the top of the list for WWI is where the use of a sub really was found to be essential to a nations war effort.

[Toon³]

Not a single vessel but I think the British Grand Fleet is certainly the most impressive sights ever seen.

http://upload.wikimedia.org/wikipedia/commons/7/7e/British_Grand_Fleet_2.jpg