A one-page info sheet on the Canal Street Sewer, which was originally an above-ground drainage route leading from the old Collect Pond to the Hudson River. (First a meandering and marshy natural drainage route from the spring-fed Collect Pond; then it became a man-made drainage ditch after European colonists began to reshape the landscape.)
I made these info sheets originally just as a way to tell people about the old streams and the sewers that have replaced them in NYC. I thought it was funny, for information about old streams that no longer existed, to present it as a flyer for a tour that didn't actually exist either. It was only a few years later than I began to develop actual walking tours where I would take people above-ground along the old routes of these streams. We only walk above-ground, but we peer down a few manhole covers along the way so that we can actually see the water flowing below (which is nowadays a mixture of natural groundwater and combined sewage together).