What happened
On Emperor Yang’s orders, older waterways were joined and extended into a canal system running from Hangzhou in the south toward Luoyang and on toward the Beijing area, linking the Yangtze and Yellow River regions.
Background
The work was carried out by millions of conscripted laborers. The human cost was heavy, and it helped bring the Sui dynasty down.
Consequences
Grain from the productive south could now feed the political and military north, making the canal the economic spine of later dynasties. Rerouted and maintained under the Yuan and after, it remains the world’s longest artificial waterway and was inscribed as UNESCO World Heritage in 2014.