Lost Vegas?

Dear Joey, you can't stop thinking about Las Vegas.  Yesterday I asked what the funnest thing you've ever done was and you said, "Go to Las Vegas." Then you said, "Go to the museum at Las Vegas."  Yesterday morning you said to me out of the blue, "Mom, why do they call it Las Vegas?  Its just sounds lost...
Maybe some people don't know where Las Vegas is so maybe that's why its called Las Vegas." Funny boy!