Dr David Livingstone was a Scottish minister and missionary who wanted to end the slave trade. He discovered the Victoria Falls, which he named after the British monarch of the time.
On one of his trips to Africa he went missing. The concern grew so great that in 1871 an American publisher sent one of his reporters, the Welsh born Henry Morton Stanley, to find him.
After quite a few months on this day, 10th November 1871, Stanley and his entourage of almost 200 men found Livingstone in a small village called Ujiji. According to Stanley's biography, he was found because Stanley, whilst in that area, heard a voice say in English, 'Good morning sir!' Obviously surprised to hear an English voice Stanley said, and I quote, 'Who the mischief are you?' (LOL) The man told him that he was Livingstone's servant and that Livingstone was in the village of Ujiji.
When Stanley first laid his eyes on Livingstone he was shocked at how he had aged yet put on a 'stiff upper lip' so as not to offend the man, and greeted him with those well known words, 'Dr Livingstone, I presume?'

Quotes and extra details taken from here.