30 April 2013 was the last time Queens day was held in the Netherlands. On that traditional Dutch holiday Queen Beatrix abdicated in the Royal Palace Amsterdam.
The inauguration of Willem Alexander took place in the New Church, also on the Dam in Amsterdam. His wife Princess Maxima became Queen of the Netherlands. Starting 2014 the Dutch national holiday will be celebrated on April 27th, the birthday of Willem Alexander.
Queens day is always severely celebrated in the Netherlands, especially in Amsterdam. Since 2014 King's day is celebrated just as much, on April 27.
The Netherlands has been a kingdom only since 1815 when Willem Frederik (King William I) became King of the Netherlands. Before this the country was ruled by the princes of Orange and Nassau and they ruled as Stadtholders (except for the periods when the Netherlands ruled by foreign occupiers).
Although the kingdom is young they are one of the only 12 monarchies in Europe that still exist today. The role of the Dutch monarchy is mostly ceremonial these days, the power of the monarch is limited.