This example shows a force-directed network of seven major cities connected by flight routes, rendered as an SVG with colored nodes and labeled text. It uses D3’s `forceSimulation` with `forceLink`, `forceManyBody`, and `forceCenter` to position nodes dynamically, while links are drawn as lines and nodes as circles. Interactive dragging is enabled via D3’s `drag` behavior, allowing users to move cities and observe the simulation react. The node colors come from `d3.schemeSet2`, and all elements update on each simulation tick.