Our verdict
A striking monument in a genuinely unusual setting, but check access before you go — call the SPTA Walks Line on 01980 674763 or check for red flags and signage, and never leave the marked byway. Not a spot for a spontaneous visit; plan ahead.
A large Neolithic long barrow just below the crest of Copehill Down, and the first ancient monument the National Trust ever bought. It sits inside the Salisbury Plain Training Area, reached on foot along a byway heading south-west from the A360 opposite West Down Camp — this is genuinely working military land, so expect to see (and hear) tanks, troops training and blank-fire exercises along the way.
National Trust land — usually free to walk; some sites charge for parking.