A choropleth map of the United States displays state boundaries and allows users to click any state to zoom and center the projection on it. The visualization is built with D3.js version 3, using `d3.geo.albersUsa` for the map projection and `d3.geo.path` to render the geographic features from a TopoJSON dataset. Clicking a state triggers a smooth animated transition via `g.transition()` with a 750ms duration, scaling and translating the entire group of paths to focus on the selected state, while clicking the background resets the view. The interaction uses D3's selection and classing methods to highlight the active state in orange.