The Big Dig, one of the USA’s most ambitious public works projects, transformed an elevated highway into a tunnel, burying it deep beneath downtown Boston. Construction lasted from 1991 to 2007, finally culminating in a new central highway – an artery that runs directly through the heart of Boston.

However, recent news suggests that it wasn’t just the I-93 that was buried. A mysterious advertisement in the classified section of last week’s paper claims that untold treasure lies hidden beneath downtown Boston. The anonymous author alleges to have buried the riches during the Big Dig, and provides a P.O. box for interested challengers to contact. Most people have dismissed the announcement as attention-seeking twaddle, but you believe otherwise.

After sending a letter to the mysterious author, you received a packet containing a series of puzzles and instructions. In addition to that, you and your fellow investigators have a map of where construction occurred during the Big Dig. Armed with this knowledge, you plan to find the prize, quit your jobs, and abscond into early retirement on a tropical island.  

Best of luck!