Eyes That Do Not See? The Practice of Sustainable Architecture

Under New York law, roof-top water towers are invisible. The terms of the code are not vague; the silhouette of a water tower and the shadow it casts are transparent to the zoning envelope and the sky-exposure plane. This is not, of course, truly mysterious; it results from the neglect of a small effect in the guarantee of sufficient light at street level. But water towers are invisible in quite another sense and this raises useful questions about architecture.