How has the United States' biggest city "built" and changed over time? Urban Layers provides a first-hand look. Using data from PLUTO and the NYC Building Footprints, Urban Layers tracks New York's evolution from the 1700s to 2013. The interactive map invites users to "navigate through historical fragments of the borough that have been preserved and are currently embedded in its densely built environment." As visitors will find, certain periods were monumental for the growth of New York's "built environment." Upon entering the site, pop-up boxes provide users with basic navigation instructions. For example, the sliding bar at the top of the site adjusts the time period, and the color-coded legend in the bottom-left-corner helps decipher the date and era of each building. Urban Layers is an award-winning project of Morphcode, "an architectural practice working at the intersection of design and technology." Check out the About tab for details on the project's creation and team. Readers interested in dabbling in their own data mapping projects may enjoy Morphcode's online Mapping Urban Data course, linked in the Learn section (readers should note that there is a fee to enroll in this class).