At least two vertically-oriented lighting columns are respectively arranged on opposite lateral sides of a space that is at least partially enclosed, so as to be perceptible within a viewer's peripheral vision without obstructing or otherwise interfering with the viewer's primary field of focus. The structure that encloses the space defines a horizontal reference. A sensor detects angular movement of the structure, such as roll and/or pitch, and a controller illuminates points on the first and second lighting columns to define an angle with respect to the horizontal reference, which varies inversely relative to the sensed angle of movement. A virtual horizon represented by the defined angle provides orientation for the viewer, to reduce the likelihood of motion sickness.