The name for such a hole is "caldera" which is a word of Spanish origin meaning "a pot" or a "cooking pot" (thing of cauldron!) - and this word is used because it resembles the shape of this hole.
Often the Calderas are filled with water forming lakes and often there is an island in the middle of the water.
Answer:
Cities grew as they became sites of industrial production, centers for banking and other financial networks, the intersections of continental trade routes, and access points for global empires. Other European cities experienced similar or even more rapid periods of growth.
9 of the states had to agree before a law was passed.
