Hello how may I help you? I would like to know a world record. Sure, I can help with that. Which one? What's the biggest city in the world? Tokyo, Japan. How many people live there? 36 million. Woah, that's a lot! It must be crowded there! Yeah, if you used the same population density as Tokyo, you could fit the world's population into Pennsylvania. That is really nuts. Thanks for all the info. sure!