HMS Dreadnought

This was the first battleship to be completely armed with only the largest guns possible, ten 12-inch cannon. Constructed for the Royal Navy in only one year and launched in October 1906 it displaced 17,900 tons (5,000 tons of that was armour) and was capable of 21 knots with it's new steam turbine engines.

It had made all prior battleships obsolete and became the first in a new series of battleships built in the Anglo-German naval race. It was made obsolete itself within ten years by the arrival of the super dreadnoughts, although it was not decommissioned until 1922.