What did Shing Huang-ti connect to make the great wall of china?

Shing Huang connected, lengthened and fortified the walls to protect the northern border of china and the subsequent dynasties, most notably the Ming dynasty maintained and rebuild it.

Explanation:

Great wall of china is largest human built structure in the whole world. It was built to safeguard the empire from the frequent raids of nomadic tribes of Mongolia and Manchuria. First emperor of China Qin Shing Huang is considered to be the Father of Great wall of China.

He unified all the states who had built the great wall respectively into one single country. It was built in order to keep the invaders away from the country. Not only the wall served to be the defensive strategy but also played a major role inn becoming the major transportation route improving and regulate the trade of china.