Answer: While building the city Tenochtitlan on the islands of lake Texcoco, the Aztecs faced swampy lands with no foundations and soil that was bad for farming.
Explanation: Because the islands in lake texcoco did not have very solid ground, the Aztecs had trouble building their city. They overcame these challenges by building canals to reroute the water.
The alliances are the main reason behind World War 1 because they turned what was meant to be a brief war between accuser and accused into a world war.
