This example shows an interactive map of New York cities and towns that zooms into a selected region on click, highlighting the active area in sky blue while fading other boundaries. Built with D3 v3, it uses `d3.geo.albersUsa` for projection, `d3.geo.path` for rendering TopoJSON features, and a `g.transition` with scaling and translation to animate the view. State and town borders are drawn as SVG paths, with click handling on both the background and individual regions to toggle zoom.