This treemap shows the italian provinces grouped by region. Each province has an area proportional to its population. Lombardia is the most populated region and Rome is the most populated province. Valle d'Aosta is the least populated region and Ogliastra is the least populated province.
Modified http://d3js.org/d3.v3.min.js to a secure url
https://d3js.org/d3.v3.min.js