Anyone who has been by the National Gallery of Art’s East Building at night has probably noticed an eerie light shining from all angles of the I.M. Pei-designed structure. This DCist photo may make you wonder what’s going on inside. It’s not a radioactive substance; it’s not an artistic statement pushing the Green Party agenda at the foot of a bi-partisan Capitol Hill. It’s the work of the late artist Dan Flavin, who revolutionized the use of light as an artistic medium.

The exhibition is the first major retrospective of the Flavin’s work, which the National Gallery describes as some of the “most important and influential” of the late 20th century.

Since the entire building seems to be emitting green light, it is a bit disappointing that the Pennsylvania Avenue facade has some scaffolding up, obstructing part of Flavin’s showcase piece. But the overall effect of Flavin’s work on the building is quite impressive, something Pei may have never envisioned when he designed the East Building.

For more on the exhibition, including what some of the critics are saying, check out the jump.