The Standing Stones of Callanish are a group of ancient megaliths located on the Isle of Lewis in the Outer Hebrides, Scotland. Dating back to around 3000 BC, these stones are arranged in a cross shape, with a central stone circle surrounded by a series of other stones. The site is believed to have been used for ceremonial and astronomical purposes. The stones are made of local gneiss rock and vary in height, with the tallest standing at about 4.5 meters. The Callanish Stones are one of the most significant prehistoric sites in Scotland, attracting visitors and researchers interested in ancient cultures and their practices.