Netherlands
We made a few side trips, too, to Kinderdijk to see windmills, and to Keukenhof to see the amazing flowers. I've put up two galleries from Keukenhof alone (click here for one, and here for the other). When you go to Keukenhof, be sure to go when the gardens are open, usually mid-March until mid-May.
In Noordwijk, there is a Flower Parade, similar to the Rose Parade in Pasadena, but the floats are made of tulips. See the separate gallery of the Flower Parade for photos of that very fun event (click here).
Click on a pic to see a slideshow with larger images.