This interactive scatter plot shows the relationship between GDP per capita and happiness scores for countries worldwide, with a dropdown menu allowing selection of individual years from 2015 to 2022. Each circle represents a country, positioned by its economic output and well-being score, while color encodes healthy life expectancy using a sequential plasma scale via d3.scaleSequential. Tooltips provide detailed country-specific values on hover. Built with D3 v7, the visualization uses d3.csv to load external data, SVG circles with enter/update transitions for animated year changes, and d3.axisBottom/d3.axisLeft for the coordinate axes.