A section of the South West Coast Path in Dorset has been destroyed by a massive landslip.
Portland Coastguard said the cliff fall happened overnight at St Oswald's Bay, east of Durdle Door.
A coastguard spokesman said: "It is huge - a massive fall has taken out part of the cliff. It is rather extraordinary."
The path has been sealed off by council workers. People have been advised to keep clear of the affected area.
A spokesman for the Lulworth Estate which owns the land called it a "substantial" landslip.
Nick Kelly said the estate would co-operate with the county council in re-routing the coast path away from the area of the cliff fall.
He said cliffs along the Dorset coast were in a "fragile" state because of wet weather over the past 12 months, followed by recent dry conditions.
"Visitors should exercise awareness of their surroundings and pay attention to warning signs when walking near the cliffs," he added.
However the Maritime and Coastguard Agency Twitter account later posted a photograph of people still walking along the path, with the caption: "What do you think they are doing on the edge of a collapsed cliff? There's a reason we give advice."
Jurassic Coast manager Sam Rose said 20m (65ft) of the coast path had fallen away,
"The rock has fanned out on the beach so it looks rather spectacular. It is an unusually large fall for this area."
Earlier this month several landslips happened at nearby White Nothe and a section of cliff came down on Swanage beach just before Christmas.
Dr Simon Boxall of the University of Southampton described the latest landslip as "awesome" and said it was likely the fall happened "in one sudden go".
"It is a relief this didn't happen during a busy weekend. There would have been very little warning anything was going to happen.
"It's very difficult to predict where and when these landslips are going to happen," he said.