EDITOR'S NOTE: This article is cross-posted from Spacing Atlantic. So, why density? Residential density, the number of people living in a given area, is one of the most important characteristics of urban areas. High densities create vibrant streets, support main street commercial areas, and encourage walking, biking and transit use. But how dense should our neighbourhoods be? What types of buildings create high densities? What do high density neighbourhoods look like? Hopefully this series encourages people to look around their neighbourhood and ask: how does density affect the quality of my neighbourhood? Without further ado ...