Diagram explaining the winter solstice at Newgrange. Every year, at the time of the winter solstice, the sun shines directly along the long passage into the chamber for about 17 minutes as it rises. The alignment with the sun is too precise to have occurred by chance. The sun however, does not enter the passage at Newgrange through the main entrance, but rather through a specially contrived opening, known as a roofbox, which is directly above the entrance.
