The Sui dynasty unified China in 589 AD after nearly four centuries of division. Emperor Wen and Emperor Yang carried out massive projects, most famously the Grand Canal, which connected the Yellow and Yangtze Rivers.
Legend says the construction was so immense that thousands of workers died, and Emperor Yang was cursed by the spirit of the earth for disturbing its veins. This hubris and the disaster of the Goguryeo wars eventually caused the dynasty to collapse after only 37 years, but it paved the way for the Tang dynasty's glory.