This visualization displays World Cup match attendance on a Mercator projection world map. The geographic outlines are rendered as SVG paths from a GeoJSON file, with each country filled in light blue. Attendance data from a TSV file is grouped by year, and for each year, the geographic coordinates of host cities are averaged to determine a central point. The total attendance for that year is then represented as an orange bubble, with its radius scaled using a square-root scale proportional to attendance. Bubbles are semi-transparent with black strokes, allowing viewers to compare attendance across World Cup years at a glance. The visualization uses a fixed map scale and translates the projection to center the map within the SVG canvas. Data is loaded asynchronously using D3 v3, with geographic boundaries drawn from a GeoJSON world map and attendance values parsed from a tab-separated file. The bubble positions are calculated as the mean projected coordinates of the host cities for each tournament year.Mercator Map with Bubbles is an SVG-based D3 visualization that combines a light-blue Mercator world map with orange, semi-transparent bubbles. Each bubble represents total attendance for a World Cup tournament year, positioned at the average coordinates of the host cities. Bubble size is scaled by the square root of attendance, allowing quick comparison of relative magnitudes across tournaments. The map is rendered using D3 v3 and data from a GeoJSON world map and a TSV of World Cup attendance.