The Netherland's National Day is Koninginnedag or in our language Queen's day.

It's on the 30th of April. The Queen's mother, Juliana, was born that day.

The Netherland's Queen, Beatrix, was crowned on the 30th of April 1980. Her birthday is 31st January but she celebrates it on Koninginnedag. Her son, Prince Willem- Alexander will probably be crowned on a 30th of April in the future. That would be the first king Holland had in years.