How many Dunkin’ iced coffee cups would it take to fill the Dorchester sinkhole? Boston Archaeology did the math Updated Dec 17, 2020; Facebook Share Four-thousand-six-hundred-and-fifty-three: That’s the number of medium Dunkin’ iced coffees it would take to fill a mysterious 16.5-foot hole discovered in Boston earlier this month. A park-goer stumbled upon on the cavity at Ronan Park on Dec. 6. Their discovery followed a rain storm that caused dirt to slump down the significant sinkhole, authorities said. City officials later revealed the cavity, which has come to be called the Dorchester sinkhole, is actually a 19th century well that was buried under 10 feet of fill used to make the park in the early 1910s.