To call attention to issues of light pollution and the lack of green space in cities, Luzinterruptus, a street art collective in Spain, created an eerie sidewalk installation of "mutant weeds."

Dispatches about Planet Earth See full coverage

The impetus for the project came when the city of Madrid eased restrictions on the brightness of 24-hour pharmacy signs. The group explains that now "so much light emanates from the new crosses that the environment that surrounds each pharmacy is permanently tinted a deep, vibrant and unnatural green color." They responded by creating rogue patches of glowing grass that matched the hue of the signs. The installations were temporary, lasting only one night, but Gustavo Sanabria documented the project in photos and time-lapse video.

On their site, the group (whose members are anonymous) describes the process of creating the malas hierbas mutantes:

Without wanting to play down such a serious subject, but trying to approach it with a sense of humor, which never hurts, we carried out our installation Mutant weeds in which we recreated a not-too-distant future, in which a new and hardy species of photosensitive plant, grows in the asphalt around the pharmacies, nourished by the photosynthesis of its powerful “low” light.

To accomplish this mission, we acquired fluorescent sticks, which we gave the form of blades of grass and we placed them on the pavement, converting the reflections into small radioactive fields that produced a curious anticipation in the many citizens who walked the streets at those hours.

We chose three downtown locations and there we left our illuminated fields for a while, while, we talked with the curious pedestrians, after which, we picked everything up so as not to pollute.

In a post about the street art installation for Atlantic Cities, John Metcalfe points out that Madrid generates so much light that it's glaringly bright -- even from space

For more work by Luzinterruptus, visit

Via Fubiz.