The Chinese constructed the "Great Wall of China." Some difficulties they had to face was possible invasion whilst they were vulnerable and focused on building the wall, invading animals, foreign lands, malfunctions with the building materials, (great stone blocks,) and possible death, since they were building in sometimes treacherous conditions.
Here are the answers to the given questions above. The most significant and and sea routes in the fourteenth century would be the silk roads that linked all European landmasses. S<span>ea lanes carry over heavier items. </span>The societies that tended to control and profit from these routes are the Mongols.
