I heard about it on the radio so that is how I know it must be true.
Everyone knows the Titanic sank many years ago on the way to New York. What is less know is it contained a cargo of mayonnaise from Europe intended for Mexico which was the next destination. Everyone knows the people of Mexico love mayonnaise (the Mexican coworker I told this to was surprised at this). When the people of Mexico heard the anticipated cargo was lost, they were greatly saddened. They have mourned the sinking of the mayo ever since on the 5th of May.