Imagine you're watching a runaway trolley barreling down the tracks, straight towards five workers. You happen to be standing next to a switch that will divert the trolley onto a second track. Here's the problem: that track has a worker on it, too — but just one. What do you do? Do you sacrifice one person to save five? Eleanor Nelsen details the ethical dilemma that is the trolley problem. [Directed Eoin Duffy, narrated by Addison Anderson, sound by David Kamp].