“Up high, on the shelves,” Sarah explained, “you can almost see the whole world! I just went on that giant slide! I didn’t know I was going to fall so far, though.”“You climbed all the way up there?” Sam asked. He had never dared to go all the way to the top.“Sure,” Sarah said. “I’m an explorer! All explorers climb.”Sam shook his head. “Well, that’s not a slide. You just went down the side of a pyramid!”“A what?”