—Wilma Dyer, Cañon City, Colorado Think beyond water! The Ural Mountains (plus, to some extent, the Caucasus Mountains) have long been considered to mark a distinct boundary between Europe and Asia. Yet our seven-continent model is only one of many standards taught around the world, mostly due to history and cultural preference. A six-continent model is preferred by most geographers, but more than one configuration exists. For example, one includes Eurasia (Europe and Asia combined). But another combines North and South America (the Americas) instead, with Europe and Asia separate.