From 1741 to 1747, Dobbs managed to stimulate exploration, the result of which convinced most people that such a passage did not exist.

Although this seems very, very unlikely, it is true that a passage of some sort does exist.

Many secret passages and hidden rooms exist within the walls of the old house.

While a northwest passage to the East does exist, it requires sailing through far northern waters that are icebound much of the year.

Several underground passages exist at the school that would have served to shield the public in the event of nuclear attack.

Some other passage must exist - one that would be known to Kwa alone!

While a hall and a passage from the medieval period still exist, the associated windows did not survive.

"And how do you know the passage exists?"

Did they even remember that the passage existed?

At that time, no subterranean passages existed in the area you indicated.