A small bit of sunlight makes its way into the cavernous depths beneath Interstate 280 where the tracks emerge from Caltrain tunnel #1, San Francisco.

Shot with the Nikon D70s and the 18-70mm f/3.5-4.5 zoom at 70mm, ISO 400, f/5.6, shutter 1/320 sec. Exposure, saturation, highlights, and color adjustments in Aperture.