|"Is this all real? Or has this been happening inside my head?"
The topic of this article is of a real-life subject that has been mentioned "in-universe" in a canon source. The Harry Potter Wiki is written from the perspective that all information presented in canon is true (e.g., Hogwarts really exists), and, as such, details contained in this article may differ from real world facts.
In 1754, celebrated broom fliers Silvio Astolfi, of Italy, and Torquil McTavish, of Scotland, agreed to hold a race from Aberdeen to Rome. Fans of both racers gathered at the Colosseum, where the finishing line was located, and a fight broke out between them. During the scuffle, an explosion was somehow set off, leaving the Colosseum in ruins. Thanks to Orabella Nuttley, who stepped forward to repair a few columns with the Mending Charm she had invented, the damage to the ancient amphitheatre was undone by the time that Rome's Muggle citizens arrived at the scene.