The Cotswolds owe their appearance to a sheep. The Cotswold Lion, a long-fleeced breed grazed here from the medieval period, produced wool so valuable that by the fourteenth century England's export trade ran largely through this stretch of Gloucestershire hills. Merchants converted fleece money into stone. That is why villages of two hundred people carry churches sized for cathedrals. The stone itself is oolitic limestone, laid down in a shallow Jurassic sea roughly 170 million years ago. It runs in a band from Dorset to the Humber, and the Cotswolds sit at its widest point. Quarried locally at Painswick, Guiting and Taynton, it weathers from pale grey to deep honey depending on iron content in the bed. Christopher Wren shipped Taynton stone to Oxford and to St Paul's. Anyone taking a cotswolds private tour from bath is travelling across the same geological seam that built both cities. The wool boom ended. Flemish and Spanish competition, then mechanised mills in Yorkshire, drained the trade by the eighteenth century. Poverty preserved what prosperity had built: with no money to rebuild, the villages simply stayed. Bibury's Arlington Row, a row of weavers' cottages converted from a fourteenth-century monastic wool store, survived because nobody could afford to replace it. William Morris called Bibury the most beautiful village in England in the 1870s, and the description stuck. Protection came formally in 1966, when the Cotswolds were designated an Area of Outstanding Natural Beauty — at 2,038 square kilometres, the largest in England and Wales. The designation covers 4,000 kilometres of drystone wall, built without mortar in a technique that predates Rome. Castle Combe, with its market cross and single main street, has no visible television aerials by local covenant. Chipping Campden's Market Hall, built in 1627 by Sir Baptist Hicks for the sale of butter and cheese, still stands open to the weather. Stonehenge and Avebury, joined to many Cotswolds itineraries, belong to an older layer entirely: Avebury's henge, raised around 2850 BC, encloses part of a working village and remains the largest stone circle in Europe. Bath, the departure point for most Cotswolds villages day tours, adds a Roman and Georgian chapter to the same limestone story — the city's crescents were cut from Bath stone, the same Jurassic bed reaching south. A cotswolds private tour from bath, in that sense, is one continuous quarry, read across ninety miles.