In 1911 the little town of Nakhla in Egypt was the scene of one of the most remarkable events in historym when a chunk of rock fell from the sky and killed a dog. This is the only known canine fatality caused by a cosmic object. Improbably though this encounter was already, its truly extraordinary nature was revealed only decades later when scientists found that the culprit was not a common-or-garden meteorite, but a piece of the planet Mars.