I'm only mentioning this story partly because I love the idea of finding lost tombs; the other part is because I know an awful lot of people with cats. So, basically, a pair of people living in Rome decided to follow a cat which had rushed past them and was meowing, and in doing so they (or rather the cat) found a two thousand year old Roman tomb that had been lost to history.
One of the joys of living in Rome is the sheer amount of history around you, above and below ground, something you don't really get where I live, and if you poke around you can find things. It's believed the tomb dates to between the 1st century BCE to 1st century CE, and the entrance had been opened by heavy rains, allowing the cat to get in. The Guardian has a quote from one of the people who followed the cat, calling the find "the most incredible experience" of his life.