Knowth is Ireland’s most spectacular complex of prehistoric passage tombs. This World Heritage site dates from about 3000 b.c and is not only the largest of the three great passage tombs in the Boyne Valley (the other 2 being Newgrange and Dowth) but also contains 30% of all the megalithic art found in western Europe. This site has been occupied and used for different purposes for thousands of years by different groups including the Beaker people (named for their distinctive style of pottery), High Kings, early Christians, Normans, farmers, and everybody else in between. The primary monument at Knowth is the central great mound, which measures 80m by 95m in size and is outlined by 127 kerbstones, many of them decorated with carvings. Inside the great mound are two passage tombs, one facing directly west and the other directly east. The two do not meet but terminate very close together at the center of the mound. Both passages are lined with decorated carved stones known as orthostats. There are also many beautiful and mysterious examples of ‘hidden art’ (carved on the backs of the massive kerbstones) of spirals, lozenges, crescent shapes, and serpentiform. Scattered around the central mound is 19 smaller satellite passage tombs. At least two of these were built before the great mound, and some have decorated stones. Access to Knowth is by guided tour only.