The Nebra sky disk is a bronze disk of around 30cm (1ft) diameter, patinated blue-green and inlaid with gold symbols. These are interpreted generally as a sun or full moon, a lunar crescent, and stars (including a cluster interpreted as the Pleiades). Two golden arcs along the sides, marking the angle between the solstices, were added later. A final addition was another arc at the bottom surrounded with multiple strokes (of uncertain meaning, variously interpreted as Solar Barge with many oars, as Milky Way or as Rainbow).