Malta's famous Azure Window rock arch has collapsed into the sea after heavy storms.
Prime Minister Joseph Muscat said the news was "heartbreaking".
A study in 2013 said that while erosion was inevitable, the structure was not in imminent danger of collapsing, the Times of Malta reports.
The popular limestone arch on Gozo island was featured on the first episode of the HBO series Game of Thrones and in several films.
Officials had recently introduced signs and a fine to stop people from walking across the landmark but they were often ignored.
Malta's Prime Minister Joseph Muscat said on Twitter: "Reports commissioned over the years indicated that this landmark would be hard hit by unavoidable natural corrosion. That sad day arrived."
Roger Chessell, from the village of Xaghra, told the Times of Malta: "There was a big raging sea beneath the window. Suddenly, the arch collapsed into the sea."
Strong gale force winds hit Malta on Tuesday, leading the Gozo Channel ferry company to suspend its services, the report adds.
It also said that many residents went to the site to see what had happened.
The Azure Window was one of Malta's most famous landmarks.
Tourists have been filmed jumping off the arch into the sea, dislodging clumps of rock in the process.
For those mourning the loss, there is a second, less well-known arch at nearby Wied il-Mielah.