5. Mars meteorite ALH 84001

These space “mushrooms” were not the first claim of alien life. On August 7, 1996, the then-President Bill Clinton stood on the White House lawn and announced the possibility that scientists had discovered the ancient, fossilized remains of micro-organisms in a meteorite that had been recovered from Antarctica in 1984.

The meteorite, ALH 84001, is one of a handful of rocks we have from Mars. These were blasted off the surface of the planet by volcanic eruptions or meteorite impacts, drifted through space probably for millions of years, before ending up on Earth.