the mongols were responsible for one man made wonder of the world( not one of the original 7 i guess)
the great wall of china was built to restrain them
The great wall of china did exist before that the current reinforced on is frpom 1300s and genghiz Khan did cross the great wall
mongols went down because of several reasons. the primary one was when they were at the gates of vienna a conquest that would have ensured their survival for many more centuries they had to return to mongolia to elect a new leader( the old one had died)
He Was succeed by Ogdai Khan and The Kublai Khan The great Khan as hes popularly known and he founded the Yuan dynasty of China so from mongolian warrior tribes he gave rise to a great chinese empire which even Marcopolo visited....Even our own Kulothunga was supposed to have spent some years in the coursts of Kublaikhan during the reign of his uncles as the chola envoy