For The Kids, Center Parcs

If you were traveling with children in Europe, wouldn't it be nice to have a "home base" to start from?  That place would need large, family friendly lodging, with plenty of activities for both kids and parents for those "stay in the hotel" days, and a staff fairly fluent in English.  It would also have to be affordable, and located pretty near the spots you're thinking about visiting.
Amazingly enough, such a place does exist.  Center Parcs has a chain of twenty locations spread across Europe, with resorts in France, England, Belgium, Germany, and the Netherlands.  They haven't done much advertising in the United States, so most American travelers don't even know they exist.
The distinguishing feature of each of these resorts is the big dome that houses the kid's activity area, restaurants, shops, spas, and pool--though "pool" hardly does it justice, since it has water slides, kiddie pools, wave pools, and more.  The restaurants cover the full range from fast food to gourmet specialty, and there's even a supermarket.  
Each resort offers a variety of kid-friendly activities.  They have activities like Baluba and Experience Factory, which are a roomful of play equipment and toys to climb on, plus petting zoo, pony rides, climbing walls, and even snorkeling.
For adults, each resort has shopping, saunas, bicycle and hiking trails, swimming and skiing, and more.
All of the resorts are located fairly near to landmarks and cities (like Waterloo, Antwerp, the Hague, and Paris), so they make a perfect "home base" from which to explore Europe.
What's more, the cottages at each resort are roomy and comfortable, because they were designed to handle a three-generation family.  Most have fireplaces, widescreen TV, children's beds, and private balconies.  As a special feature, families can even reserve a room with a puppet theater, circus tent, baby bath, and collection of toys.