Manhole mystery grips New York – just what are city’s ‘mole people’ up to?

It started in early May. Under cover of darkness, three people pried open a manhole cover in Queens, New York , and clambered down into the sewer. The incident might have gone unnoticed, but the subterranean quest, which was caught on film, captured New Yorkers’ interest when it happened again, and again, in the same month, with two other groups filmed making their way in and out of the sewer system in Brooklyn. …