The sarsen trilithons at Stonehenge weigh up to 25 tonnes each, yet were erected without metal tools around 2500 BCE. The monument's Heel Stone aligns with the summer solstice sunrise, a precision that suggests astronomical knowledge two millennia before the Greek Parthenon. Archaeological surveys confirm that the smaller bluestones were quarried 240 kilometres away in the Preseli Hills of Wales, then transported by a combination of river raft and overland sledge. The engineering feat remains unparalleled in Neolithic Europe. Today, Stonehenge anchors a UNESCO World Heritage landscape that includes the Avenue processional route and hundreds of Bronze Age burial mounds. Daily visitor numbers are capped to protect the fragile chalk grassland, and entry requires advance booking. The stone circle itself stands within a roped perimeter, but the visitor centre—opened in 2013—houses original Neolithic tools, pottery fragments, and a reconstructed roundhouse that demonstrates Iron Age construction methods. Audio guides reference recent excavations that identified cremated human remains dating to the monument's earliest phase, when it functioned as a cemetery for elite families. Paired day trips from London often combine Stonehenge with the Cotswolds, a 2,000-square-kilometre limestone upland 130 kilometres northwest. The region's honey-coloured villages—Bourton-on-the-Water, Bibury, Castle Combe—were built during the wool trade boom of the 14th to 17th centuries. Cotswold limestone, quarried locally, weathers to a golden patina and defines the Area of Outstanding Natural Beauty designated in 1966. Dry-stone walls, thatched cottages, and Norman churches remain intact because modern development was restricted by conservation orders. Full-day excursions from London typically depart between 08:00 and 09:00, allowing a mid-morning arrival at Stonehenge before the peak afternoon crowds. Coaches stop at Windsor Castle or Oxford University on the return route, creating a three-site itinerary. Smaller group tours limit capacity to 16 passengers and provide guided commentary on Roman roads, Saxon settlements, and the evolution of Cotswold vernacular architecture. The Stonehenge ticket—priced at 32 GBP when purchased on-site—is bundled into most tour packages, as is motorway toll access from London hubs.