Warning: The following accidents may have caused irreparable harm to individuals and/or the fabric of space-time. Proceed with caution.
In 290 AD, a time traveler prophetsed that a devastating earthquake would strike the Library of Alexandria, causing it to burn to the ground. The earthquake never came, but the time traveler, convinced of their own foresight, still set fire to the library, ensuring the destruction of countless irreplaceable texts.
Caused the loss of: 1.3 million scrolls, 2 dozen librarians, and the knowledge of the entire known world.