This example presents a world map with red circles marking a curated list of cities, including Tokyo, London, and Easter Island. The map is built using D3.js version 3 with a Mercator projection and TopoJSON data for country boundaries. Users can pan and zoom the map via the d3.behavior.zoom API, while a tooltip-like styled div is defined but not activated. City coordinates are projected onto the SVG canvas using d3.geo.path.