On 1st August 1798, Nelson led his fleet into action against the French fleet anchored at the mouth of the Nile in Aboukir Bay, Egypt. In a fierce action, fought in the shallows between the shoreline and the French warships, Nelson almost totally destroyed Napoleon’s naval power in the Mediterranean, leaving him and his expeditionary force stranded in the hostile Egyptian deserts.
One fact that is often overlooked about the battle is that Nelson was quite severely wounded – a piece of shrapnel, or rather a splinter from the rail of his flagship, caught him on his forehead, ripping the skin and sending a fleshy flap down over his good eye. For a moment Nelson thought he was blinded, but after being treated soon returned to command the action with a bandaged head, as seen in this illustration below.
You can read more about this event on British Battles and the Naval History and Heritage Command website.