Sentence:  They sank twenty shafts in a ring round the central <WSD>money pit</WSD>, and drove tunnels endlessly in the hope of intercepting the underground channel and so draining the treasure shaft. 
Meaning of the word marked with <WSD> tags:  Long-standing nickname of a complicated, seemingly man-made excavation on Oak Island in Nova Scotia, Canada, rumored to contain pirate treasure and which has been repeatedly and unsuccessfully probed at great expense.