the original, Chicago Children's Museum, founded in 1970, began with educators, artists, librarians,scientists,grass-roots- neighborhood folk,people who actually knew what children needed. and one of the things they don't need , is to be underground. Children are not moles, worms, carrots,etc.
Unless they are excavating for some reason, they should see the sun, grass,the sky, the birds, etc. And while it would be nice to be in a park-like setting. It should be one where the space is given...