Sui 

China hadn't been united since the fall of the Han dynasty. In 581 AD the sui dynasty was founded by Wendi. He later declared himself the first emperor of the sui dynasty, his biggest accomplishment was the grand canal. This connected the Hunge He and the Chang Jinag, this connected the rice growing south to the metropolitan north. This was good for the dynasty because it created trade between both sides of the dynasty. The Great Wall of China was another accomplishment of the Sui Dynasty because it was a very effective way of keeping out the surrounding groups.  While this was a clever precaution to take the endless labour and high taxes caused the Sui residents to rebell against the government. This caused the  Sui Dynasty to fall after there second ruler was assassinated in 618 AD.