Museum Gardens occupy the former grounds of St Mary's Abbey, a Benedictine monastery founded in 1055 and dissolved by Henry VIII in 1539. The ruined west front and a substantial section of the church's nave walls still stand, roofless and ivy-clad, giving the garden its centrepiece. The scale of the ruins makes clear how large the original abbey was — before its dissolution it was the richest and most powerful monastery in the north of England. The gardens are enclosed by a wall and free to enter; they are at their best on a sunny afternoon.
At the northwest corner of the gardens stands the Multangular Tower, a ten-sided Roman tower dating from the early 4th century that survives to almost its full original height. It is one of the finest pieces of Roman military architecture in Britain. The gardens also contain a small observatory and the Yorkshire Museum, which occupies a Neoclassical building constructed on the site in the 1830s. Squirrels are numerous and entirely unafraid of visitors.