This site has a really neat graphical way of representing population and area sizes (based on cia world factbook). You can change a ton of different views and filters, and also view by continent. Pretty neat stuff.
The notes are also amusing, and underline the difficulties that map-makers run into, even if they are demonstrating a proof-of-concept relational map. “How do we represent Palestine or Taiwan” are obvious problems, but less obvious ones include “do we count Greenland when representing Denmark’s population density?”