My wife and I first learned about Apenheul on a nature show of some sort, and pledged that we would…read moresomeday visit. About five years after the fact, we found ourselves in Amsterdam and took the one hour train trip (and subsequent shorter bus ride) to one of the coolest places I've ever had the pleasure of seeing.
Primates of all sorts roam freely through the park, allowing visitors to observe and interact with them in a way that goes well beyond what one could experience in a typical zoo.
Admission is €19.50 for adults and €17.50 for children, and the park is open from the end of March through the end of October. For the not-so-adventurous, travel is fairly straightforward, with direct train service to Apeldoorn from Amsterdam Centraal in the morning, and back in the afternoon. Buses between the train station and the park run regularly, taking about fifteen minutes each way.
For the tourist, with so much to see and do in Amsterdam, it might seem hard to justify spending a day looking at monkeys. It is, however, very rewarding and worthy of anyone's time.