the art of war

The earliest seismograph in the world-

The seismograph invented by Zhang Heng in the Eastern Han Dynasty

The earliest existing metal firearms-

Xixia bronze cannon

The earliest navigation instrument in the world-

"Sina" in the Warring States Period

The earliest gunpowder weapon in the world-

The first year of Tang Tianyou

rocket

The largest bronze found in the world-

Muswuding in Shang Dynasty

The oldest stone bridge in the world-

The Zhaozhou Bridge