Only a handful of people will ever see these coastal landforms, even though they are right beside the famous and busy Great Ocean Road. They were created out of sand dunes by a very high tide and a wind from the west. The next high tide, strong onshore wind or solid rainfall will see them disappear.
These sand cliffs and other forms were produced by the usual agents of wind, sand and water, but on a remarkably compressed timescale, geologically speaking. At sunset yesterday, the Mounts Bay (or Marengo Beach) sand dunes had a uniformly flat surface, indistinguishable from the dry sand on the beach save for the angle. A high tide overnight combined with a solid swell and the wind blowing over the dunes from the west saw these coastal geomorphic forms appearing not in millennia, but in hours. The same processes will remove them in days. The net result will be sand removed from the dunes and washed out to sea. These intricately sculpted sand forms are sadly evidence of the serious problem of coastal erosion which is affecting many parts of the Great Ocean Road.
These dunes are under significant threat from ocean waves and tides. In an attempt to halt the advance of the erosion, they are replenished regularly with sand from further up the beach by local authorities which surprisingly are yet to come up with an effective and permanent solution to the continuing erosion at this location.
Your mind and eyes might hunt for scale when looking at these pictures, like a zoom lens on autofocus trying to lock on to something. There are sufficient clues in each photo to assist in this regard. Suffice to say, most of these features are on a much smaller scale than you might think at first glance.
The above photos were all taken with my back to this beach (known as Marengo Beach or Mounts Bay Beach), and they are all detailed closeups of the formations on the dune shown below in both directions. Some of these images were taken with a macro lens. This beach is a km or so south of Apollo Bay, on the south-east coast of Australia.