The bluestones at the heart of the circle were quarried in the Preseli Hills of west Wales and moved roughly 150 miles east. Each weighs up to four tonnes. They were standing on Salisbury Plain by about 2500 BC, and they remain the reason Stonehenge from Southampton Cruise Port tours exist at all: no other Neolithic monument in Europe contains stone carried so far by human effort. The sarsens came from nearer home, most likely West Woods on the Marlborough Downs some 25 miles north. The largest weighs about 25 tonnes. Their builders dressed each face with hammerstones, tapered the uprights so they read as straight from the ground, and curved the lintels to follow the arc of the ring. The joints are borrowed from carpentry: mortice and tenon holding lintel to upright, tongue and groove locking lintel to lintel. Nothing here is accidental. The axis runs to midsummer sunrise in one direction and midwinter sunset in the other, and the Heel Stone marks it beyond the ditch. What survives is only the centre of a much larger design. The monument sits inside a landscape of some 350 burial mounds, the two-mile Cursus, the Avenue, and the timber-post settlement at Durrington Walls two miles northeast. Excavation recovered the cremated remains of at least 58 people from the Aubrey Holes, making this one of the largest Neolithic burial grounds known in Britain. UNESCO inscribed the whole ensemble in 1986. English Heritage has cared for the site since 1984 and opens it daily, 09:30–18:00, at Near Amesbury, Wiltshire, SP4 7DE. The modern arrangement dates from 2013, when the visitor centre opened at Airman's Corner and the old A344 — which ran within metres of the Heel Stone — was closed and grassed over. The stones stand in turf again. That decision is why a Wiltshire stone circle tour now begins a mile and a half away, with the monument withheld until the last rise of the down. For cruise passengers the geography is unusually kind: roughly 40 miles separate the quayside from the plain, which is why a Stonehenge from Southampton Cruise Port tour fits inside a single turnaround day, and why Salisbury Plain landmarks appear on so many itineraries between ship and shore.