If you visit Amsterdam in April be sure to visit not only
De Wallen (where most tourist go) but also try to visit in Amsterdam,
De Heiniken experience (where people get a tour in Beer factory),
Body Worlds ( what drives a person to persuit happiness)
Keukenhof (where you can see all kinds of Tulips in their blossom) near Schiphol
Volendam ( authentic fish community) North Holland
It will enlighten your perspective and the believing in one achievement.