In the darkness of the deserted museum, something inhuman stirred. A pair of headlights swept around a corner, illuminating a statue—as a camera streamed the sight to viewers around the world. The nocturnal intruder was part of "After Dark," an event series in which robots roam a public space when the crowds have gone home.

During the first "After Dark" event, in August 2014, about 500 people got a chance to explore London's Tate Britain via one of four robots. Tate had selected "After Dark" and its creators, designers Ross Cairns and Tommaso Lanza, for its annual IK Prize, which awards technology projects that bring art to a larger audience. While one of the 500 volunteers used online controls to steer the robot, everyone else could watch a live feed as art experts provided commentary.

Viewing art after hours is familiar to Cairns and Lanza, who have produced interactive exhibits in several museums and galleries. "Working in these amazing spaces, we often walked around the galleries at night by ourselves—public spaces where we were really not supposed to be," says Cairns. "We wanted to re-create that experience."