Gondoletta is a boat ride in Travel Realm at Efteling. While it's not a "must do," it is also recommended.
A peaceful boat ride on the main Efteling lagoon that lasts twenty minutes. The boats are not much bigger than rowing boats, but designed to fit 20 people on. If you go towards the end of the day, you'll likely be allowed on in smaller groups.
Reviews of Gondoletta