the Great Wall of China

visit, call on, pay somewhere a visit / for an occurrence to come, arrive

sometime; someday

since some unclear time

long castle or wall / long line of castles / (figuratively) a person who is to become the head of state.

Great Wall of China

10000 li, or 5000 km / (figuratively) very long distance, immeasurable distances

(と〜) thinking that […] (with the next clause explaining that the truth is contrary to expectations)

to seem, to appear

continuative of the passive of 思う (omou); continuative of 思われる (omowareru)