Snowworld Zoetermeer is one of the largest indoor ski and snowboard facilities in Europe, with two main slopes of different difficulty levels, a separate learner area, and a snowtubing run. The temperature inside is kept around -4°C year-round, which is a genuinely startling experience in a Dutch summer.
The slopes are ski school-friendly — this is where many Dutch children learn to ski before heading to actual mountains — but experienced skiers use it for off-season training and the park features a terrain park with rails and kickers. Rentals, lessons, and day passes are all available on site. There is a cafe and apres-ski bar at the base, which tends to be lively on weekend evenings. Worth a visit if you have never skied in a converted warehouse before, or if the Alps are not on the itinerary this year.