This is mine.
The beach.
It is nice because my kids also find new and amazing attitudes and peace at the beach. We can do things as a family. Or, if they want some alone time, they can build by themselves. Or hunt for seashells. Or sit on our blanket and read. Or just nap.
All of these things are done at the beach on various occasions.
What more can you ask for than to have a special place you and your family can enjoy? It helps that it is all of 5 minutes from the house.