An area the size of Wales

"If it is important to get your message across then you need to do what the media and other organisations have been doing for years - use an analogy that people are more familiar with! For example, nobody knows what 20000km² looks like; but say it is an "area the size of Wales" and it suddenly becomes much clearer. "

http://www.simonkelk.co.uk/sizeofwales.html