This answer depends greatly on the time period in question, but generally speaking it is true that the presence of many rivers and mountains protected China from invaders, and allowed their culture to grow with little outside influence, with the exception of Mongolian invasions from the north.
The Romans wanted to expand to Sicily which was under Carthaginians control so they fought for it.
hope that helps :)
The Louisiana Purchase was a negotiation between France and The U.S. in 1803 where the U.S. paid $15 million for approximately 827,000 squared miles
