Use 'swarm with' to describe a place that has a huge number or amount of something all at once. After the flood, the streets swarmed with emergency workers.
Pro Tip 2/3
Lively Movement
'Swarm with' often implies a buzzing, active movement, like a crowd of bees. The playground was swarming with children at recess.
Pro Tip 3/3
Not Always Literal
Sometimes 'swarm with' is used figuratively to emphasize the abundance of something. His mind was swarming with ideas for his new book.