This is an interactive tree diagram of penguin species, showing the hierarchical classification from the family Spheniscidae down through genera and individual species such as Emperor, Adelie, and Little Penguins. The visualization uses d3.tree and d3.hierarchy to compute node positions, with SVG circles and cubic Bézier paths rendering nodes and links. Node and edge colors are driven by data attributes like type and level, while node size reflects a value property. The example is built with React and D3 v5, rendering entirely as SVG.