There's a fascinating ruin on Mount Lofty named Arthur's Seat. It was built in the late 1850s by (or for) George Tinline, a wealthy banker. It opened as a boarding school in 1927, attracting students from around South Australia. It sold again in 1941 and returned to a private residence.
Arthur's Seat was destroyed in the 1983 Ash Wednesday.
In October of 2021 it was listed for sale.