This interactive map displays world countries and a graticule on a rotatable orthographic projection, with a click on the United States switching to a Mercator projection. The visualization uses D3’s `d3.geoPath`, `d3.geoProjection`, and `d3.geoGraticule` to render SVG paths, and supports dragging to rotate the globe. Country boundaries come from the world-atlas TopoJSON dataset, while names map via ISO codes from a TSV file. The animation transitions between projections using D3’s `.transition().duration(750)`.