Tintern Abbey is one of the great ruined monasteries of Britain: a Cistercian foundation from 1131, dissolved in the 16th century and left as a roofless Gothic shell beside the River Wye. Its scale still surprises, especially when you stand in the nave and look through the empty east window toward the wooded hillside.
The abbey also matters because of its afterlife. From the 18th-century Wye Tour onward, it became a model of the picturesque ruin, painted, written about, and visited by travellers looking for landscape with feeling.