The largest and most famous Neolithic site on outer Hebrides is the Calanish Standing Stones. The are arranged in a cruciform shape with a circle inside, and we’re likely a ritual site thousands of years ago. The whole arrangement in on a hill above a lake with panoramic views in all directions. The stones are about 5,000 years old and predate the English Stonehenge. One of the explanation for the stone arrangement and location is that it was a prehistoric astronomical laboratory. The mysterious stones are fought 12 foot high and all made from local rock, Lewisian gneiss.