I know that this year is the 70th anniversary of the liberation of the Netherlands. But I can't find much information on what is going on that day in Amsterdam. And since it is a national holiday, what I can expect to be open and closed.
Yes, everyone will have the day off and will be in the mood for Margaritas. But seriously, it's not as big a party as Queen's Day (Which is now King's day, since Beatrix retired) but most of those performance stages will again be in use, not to mention the fact that they will just have gotten cleaned-up from the serious partying that goes down on April 27th. (We arrived in town on May 2nd a few years back and the sidewalks were still green with crushed Heineken cans, dusted with a confetti orange from balloons, garlands, and such.)
Veterans'/Memorial Day meets Cinco de Mayo is really a pretty good description of what to expect.
Since a picture is worth a thousand words, here's a photo of the holiday celebrating the 'House of Orange':
And here's on of an evening concert on Liberation Day:
At Westerpark in Amsterdam there will be a big Freedom festival ( Vrijheids Festival ) on 5/5/15. There will be mostly music , choirs.
Please write it down and show people when asking for directions because there's no way you will be able to pronounce it understandable to a Dutchman . Most of them speak English .
Westerpark is within walking distance of Centraal Station and Dam Square.
Because of the 70-th anniversary there will be celebrations , other years not much , not even a day off !