Eugene Atget is one of my favourite classic photographers.
He is most noted for documenting French architecture and street life - particularly in the city of Paris.
His work is timeless and atmospheric with a dark, contrasty Gothic style. Check out the use of vignette - a result of the cameras and film he was using. Makes Instagram look silly...
If you're looking at The Built Environment and you're thinking of starting with some general explorations it's worth looking hard at Atget's work. Look at the use of light, contrast and tone. Take a film and work with it in the darkroom, inspired by the 'dream-like' documentaries of Parisian Vernacular architecture.