On August 10, 1901, two British schoolteachers touring the Little Trianon Palace at Versailles encountered Marie Antoinette and several people from her era. According to them, she had been painting at the time. Mary wore a bright summer dress and a sun hat.
Her hair was long, unlike the short hair she had when she was executed. If that had been Mary's ghost, then something was clearly wrong. The ghosts at Hogwarts all retained the appearance they had at death—for example, Bloody Baron was covered in blood, and Nearly Headless Nick had his neck wound. Moreover, she was not pearly white, but as vividly colored as Peeves.
In 1911, the two schoolteachers published a book recounting their experience of getting lost. However, people quickly dismissed it as a hysterical episode, and no one paid it any attention. It was not until 1912, when someone discovered an eighteenth-century map of Versailles that marked the little bridge the two teachers had crossed near the Little Trianon Palace—a bridge absent from the tourist guides—that people began to take their account seriously.
At first, they toured the grounds like ordinary visitors. Later, they decided to walk through the gardens to the nearby Little Trianon Palace. Yet as they walked, they got lost and came upon a path that did not appear on any map. At that point, they saw a woman waving a handkerchief at them, and later encountered a gardener. In short, they felt that something was terribly wrong and hastened away.
"Maybe we should find a way to close the entrance." Lucius Malfoy strolled across the lawn, looking at The Sun overhead. "Then no more schoolteachers will vanish here."
"They were teachers from a convent." Severus looked at the people sitting in a circle some distance away, singing. They were no different