A 3D scatter plot of the Iris dataset displays flower measurements across three axes, with sepal length, sepal width, and petal length in one trace, and petal width replacing the vertical axis in a second trace. The interactive visualization uses Plotly.js with a `scatter3d` and `scatter2d` type, loading data from a CSV via D3.js `d3.csv`. Markers vary in size, opacity, and color, with the layout margins set to zero for a clean presentation.