Millennial Cities is an interactive web mapping site that aggregates and provides access to important maps, data, and map applications regarding climate change, equity, housing, demographics, and more. The purpose of including these free interactive tools on the website is to provide access to and promote the use of urban planning geospatial resources. These resources are intended to help citizens better understand their surroundings and make more informed decisions.

The evolution of web mapping applications and geographic information system (GIS) technology has presented a great opportunity for the planning community to foster spatial thinking among friends and coworkers -- the use of analysis tools, spatial data, and web maps to examine and highlight issues has never been so easy and readily available. Additionally, as an educational tool, it provides local governments with a means to promote critical information to the general public.