This bubble chart visualizes the relationship between cost of living, rent price, and population across 20 expensive global cities, with bubble size representing residents and color denoting region. It uses D3 v6 to create an SVG visualization, employing d3.scaleLinear for the x and y axes, d3.scaleSqrt for bubble radii, and d3.scaleOrdinal with the Tableau10 scheme for regional coloring. Interactive tooltips appear on mouseover, revealing city details. The chart includes dual legends for both bubble size and regional color coding, rendered from a CSV data file.