If you take a walk through some of the older neighborhoods in the United States, you might spot a slightly odd configuration on some of the houses: two front doors sitting side by side on the same facade.  It’s easy to assume these homes must have been converted into duplexes at some point, with a door added — and that may well be the case in some instances. But many of these buildings were constructed right from the start as single-family homes with two front doors, sometime in the 18th or 19th century. So why ...Read More