This is a meteorite from Mars that fell in Morocco in 2011 and it was a spectacular observed fall and lots of pieces were found. NHM bought one of the largest individual stones (over 1 kg!) in 2011/12, and this was the single most expensive acquisition of the museum in probably 2 decades or more. Meteorites from Mars are very rare – most meteorites come from the asteroid belt (between Mars and Jupiter in the solar system).