Large crowds of people fearful and furious over the way President Donald Trump has been slashing federal jobs and programs ...

Crowds of people dressed in black and holding candles ... the name of the victim was displayed on a piece of white paper stuck to a thin wooden stick. Priests prayed over the coffins as they ...

Or is it a haphazard tangle of personal trajectories, as people dodge and weave through the crowd? MIT instructor Karol Bacik and his colleagues studied the flow of human crowds and developed a ...