"If I could go to a limestone cave for my birthday, it would be a dream come true."
So of course we went. Laurel Caverns, Pennsylvania's largest cave, is about an hour-and-a-half drive southeast of us. On our underground walking tour we learned that silaceeous limestone caves like this one don't have stalactites and stalagmites (too sandy) but the sculptured walls and network of passageways were beautiful. And we did see two (sleeping) bats. This is the view from the deck of the visitor's center afterwards, looking out from Chestnut Ridge toward Uniontown.

For your youngest - the National Speleological Society's youth group page. Good caving!