According to The Guardian, the two tourists, ages 21 and 25, stepped away from their tour group on Saturday and etched a "J" and an "N" into the stone wall. Authorities said they found the carvings on the first-floor brick wall on the west side of the Colosseum.

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The women, whose names have not been released, could face a hefty fine for defacing the structure.

This isn't the first time someone has vandalized the Colosseum. Last November, a Russian tourist was handed a four-month suspended prison sentence for etching a "K" into the wall of the building. That person was ordered to pay  a £16,000 bill.