In Commonwealth Park, on the north side of Lake Burley Griffin, there's a rusty, forgotten plaque marking the place where a sculpture was buried in the mid-80s. On the other side of the lake, in the National Gallery sculpture garden, is a much-loved piece by the same artist. The artist refused to explain why he'd had the piece buried, (or moreover, why the city paid for it). In the light of your link, it must have been specifically to confuse archeologists in the future.