“Another, more ingenious method of estimating crowd size is by examining the quantity of artifacts they leave behind. To say it less delicately, one way of counting a crowd is to weigh how much garbage it leaves behind. Since sanitation trucks are weighed electronically at the disposal site, it has always been an easy matter to measure the amount of debris left after New York’s famed ticker tape parades down the ‘canyon of heroes.'” More here.
