As the title suggests, maps are as much about propaganda as they are about geography. Not all those on display are totally accurate represenations of the land, but instead are subjective images shaped by the political issues, desires and aspirations of the period in which they were drawn.
It's all very impressive, but the biggest crowd was to be seen peering at Stephen Walter's The Island, a map that sees London as independent from the rest of the UK. While more or less geographically correct, his view of the capital also offers a wealth of local and personal information. Visitors to the exhibition seemed to be keen to check out what Walter had to say about their favourite parts of the city. I was bemused to see Brockwell Park, my local patch of greenery, described as Cannabis HQ. Below is the Central London section.
See also the BBC's The Beauty of Maps - and there is still time to watch some of the excellent BBC Four programmes on iPlayer.