Pope Gregory IX was apparently a dog person, because he tried to exterminate all cats from Europe. The real Betty Boop was actually an African American woman named Esther Jones. Over 200 million people live in Nigeria, which is almost twice as many people as the second-most populous African nation, Ethiopia. The world's largest swimming pool is in Algarrobo, Chile and measures over 1,000 yards from end to end. That's 10 football fields! The Greek philosopher Diogenes the Cynic was the original Oscar the Grouch: he chose to be homeless and slept in a large ceramic jar near the marketplace. The only king without a mustache in a deck of cards is the King of Hearts