This example displays population changes over time using an animated bar chart in SVG. Bars grow in height sequentially as each year is added, with green bars that turn red and expand slightly on mouseover. The visualization is built with D3 v4, using `d3.scaleBand` for the x-axis, `d3.scaleLinear` for the y-axis, and `d3.axisBottom` and `d3.axisLeft` for ticks. Bar entrance animations use `transition().delay()` and `ease(d3.easeLinear)`, while hover effects rely on `transition().attr()` calls. Data comes from a CSV file with year and population values.