St Michael's Mount, a tidal island in Cornwall, England, is home to a castle and chapel that have been owned by the St Aubyn family since 1650. Accessible by a causeway at low tide, this historic site was once a monastery and later a priory before becoming a secular chapel. With a rich history including sieges, occupations, and ownership changes, the mount is now managed by the National Trust and remains a popular destination for visitors exploring its picturesque surroundings and intriguing past.