Italian officials are investigating reports of falling stones at Rome’s famed Colosseum. Several witnesses Tuesday said they saw large chunks of rock falling from the structure’s iconic arches, according to a FOX News report.

This is not the first time reports of a crumbling Collosseum have surfaced. Similar sightings were also reported back in 2010. Officials blamed pollution and vibrations from nearby cars and subways for the damage.

More than 6 million visitors arriving on flights to Rome visit the Colosseum each year. The 2,000-year-old structure is set to undergo a $33 million restoration beginning in March.

The improvements will reportedly increase the areas tourists can access by up to one quarter.

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