Buried deep inside a mammoth office building that occupies an entire city block in Manhattan’s Chelsea neighborhood, a delicate column of light extends 15 stories, from the roof to the ground level, illuminating a dim, windowless stairwell. The shaft’s striking glow is not generated by electricity, however, but sunlight.

Light Fall, as this light sculpture is known, concentrates and directs daylight through a roof-mounted “light cannon,” or solar collector, and fiber optics. The latter’s glass strands (more than 5,000 miles of them, bundled and sheathed in translucent sleeves) are strung between steel rings, each 15 feet apart, and supported in the stairwell by four steel cables in tension. When the sun is shining, this “light dagger” transmits daylight down its 208-foot length, with the ends of the fibers producing bright, dotlike points of light.