Tinkinswood or its full name Tinkinswood Burial Chamber (Welsh: Siambr Gladdu Tinkinswood), also known as Castell Carreg, Llech-y-Filiast and Maes-y-Filiast, is a megalithic burial chamber, built around 6,000 BP (before present), during the Neolithic period, in the Vale of Glamorgan, near Cardiff, Wales.
The structure is called a dolmen, which was the most common megalithic structure in Europe. The dolmen is of the Severn-Cotswold tomb type, and consists of a large capstone on top, with smaller upright stones supporting it. The limestone capstone at Tinkinswood weighs approximately 36 metric tonnes (40 long tons) and measures 7.4 meters (24 feet) x 4.2 m (14 ft); it is thought to be the largest in Britain, and also in Europe. It would have taken some 200 people to lift the stone into the correct position. It was originally all covered by a mound of soil, which has been removed over time, now the remaining mound behind the structure measures approximately 40 m (131 ft) x 18 m (59 ft) in size.