This visualization shows the different types of waste found on beaches, categorized by material and item, using a bubble chart. The size of each circle corresponds to the number of items found, and the color indicates the category (e.g., plastic, metal). The code uses the `d3.csv` and `d3.hierarchy` APIs to process the data, while the `d3.pack()` layout arranges the bubbles. Hovering over a circle triggers a tooltip that displays the specific category and count. The chart is rendered as an SVG with animated mouseover effects.