Newbury Street

This guide to Newbury Street in Boston looks at what's underneath the fashionable brownstones: thousands of wooden pilings driven into filled tidal marsh, which hold up fine as long as they stay wet but start rotting within years once air reaches them. The Boston Groundwater Trust monitors hundreds of wells across Back Bay, and nearby Trinity Church, resting on similar pilings, had to install a backup system to keep its own foundation soaked. Look again at the wrought iron and bay windows around you with that in mind.