If you write Day, Month and Year with two digits; then no matter how you write it: day-month-year or month-day-year or year-month-day, it’ll look like this: 06-06-06.
Remove the 0’s, and -‘s, and you get the number 666. While most people probably see it as somewhat funny but also partly uninteresting, some religious people interpret it as a possible dangerous date, where anything nasty can happen.
Hopefully it will all turn out that the most eventful moment this day, was when the clock turned 06:06 at the date 06.06.06.