Note to tourists: defacing a centuries-old monument is never a good idea.

An unnamed Russian tourist was arrested and fined nearly $25,000 over the weekend for engraving a 10-inch letter “K” into the Rome's Colosseum, reports Italian news agency ANSA

According to Roman police, the man used a rock to carve out the letter.

"The damage to the monument is notable," said Mariarosaria Barbera, an archaeological superintendent who oversees the administration of the Colosseum. “The incision cut out part of the surface of the structure and compromises its conservation and image.”

After a witness called police, the tourist was charged with causing “aggravated damage to one of Italy's most iconic symbols”--given a four-month suspended prison sentence and fined 20,000 euros-- a little over $24,800.

This is the fifth case reported case of vandalism to the Colosseum this year. In the wake of the incidents, authorities will likely add more surveillance cameras to the area and set up increased visual and audio warnings to discourage vandals.

Completed by Roman emperor Domitian in AD 82, the Colosseum receives over six million visitors annually. It is currently undergoing a large-scale restoration project to be completed in 2016.