a moving crowd
a group of many things in the air or on the ground; "a swarm of insects obscured the light"; "clouds of blossoms"; "it discharged a cloud of spores"
be teeming, be abuzz; "The garden was swarming with bees"; "The plaza is teeming with undercover policemen"; "her mind pullulated with worries"
move in large numbers; "people were pouring out of the theater"; "beggars pullulated in the plaza"