The maps presented on this website are cartograms, otherwise known as density-equalising maps. The maps of the world you are used to seeing attempt to represent countries according to their land area. A cartogram re-sizes each country (or other geographical unit) according to some other variable - for example population, GDP, number of people with AIDS, etc. In the population example, densely-populated country such as the UK will appear much larger than it does on a standard map, and sparsely populated countries will appear smaller.