One of the limestone stacks that made up Australia's famous Twelve Apostles rock formation has collapsed into the sea.
The stack took many years to reach this shape...
There were only ever nine of the limestone towers in the first place, but now the number is down to eight.
Local park ranger Alex Green said a family of sightseers were at the landmark when the stack collapsed.
...but it collapsed in seconds
One of them took a photograph just seconds before it disappeared into the sea.
"They said it sort of shimmered or shuddered and then
fractured and collapsed straight down on itself - it was
almost like a building demolition," Mr Green told the Associated Press.
"All that remains now is quite a substantial pile of rubble about 10 metres (33 feet) above sea level."
Mr Green said the collapse of the 45 metres (146 feet) tall stack was part of the natural
process of erosion that had formed the rugged coastline.
Close to the scenic Great Ocean Road in Victoria state, the Twelve Apostles draw tens of thousands of visitors every year.
The stacks are made of rock formed up to 20 million years ago, and are created by the sea gradually eroding the soft limestone cliffs of Port Campbell.
The stack that collapsed on Sunday was not the first such landmark to disappear into the sea.
In January 1990 a formation called London Bridge - a natural arch that linked the mainland to offshore rocks - also collapsed.
Two tourists were stranded on the arch until they were rescued by helicopter.
But Mr Green said there was no danger to visitors as a result of Sunday's collapse.
He added that the authorities were monitoring the safety of cliff-top lookouts nearby.