Carved Stone 8 in Gavrinis Dolmen passage grave, Gulf of Morbihan Larmor-Baden, Morbihan, France. Cairn de Gavrinis Passage Grave, the largest and most decorated tomb in Neolithic Europe with 29 six-foot-high menhirs carved with labyrinthine fingerprints. This sanctuary/tomb/shrine was used by the same family for hundreds of years
Oklahoma mystery stones. They are often mistaken for carvings made by man, but the explanation I got was, they are natural (concretions), where the softer sandstone wore away, leaving the harder, darker, patterns.
Secret Britain travel guide part one: stone circles and megaliths
Seahenge oak circle Holme-Next-the-Sea, Norfolk: Seahenge, which is also known as Holme I, was a prehistoric monument located in the village of Holme-next-the-Sea, near Old Hunstanton in the English county of Norfolk. A timber circle with an upturned tree root in the centre, Seahenge was apparently built in the 21st century BC, during the early Bronze Age in Britain, most likely for ritual purposes.
The 5,000-year-old Neolithic carvings of concentric circles, interlocking rings and hollowed cups were uncovered as part of a four-year English Heritage-funded initiative, in partnership with Northumberland and Durham County Councils (Beautiful)