What country had the largest empire and the greatest naval fleet?

The largest Empire ever forged was the British Empire spanning 33.67 million km² (13 million square miles), about 1/4 of the Earth's total land area, and encompassing 1/4 of the Earth's population.

The largest Navy in history is most likey the United States Navy as of 1945 with over 1,600 warships. The most powerful Navy in history is modern United States Navy.