"How groups of humans contemplate and plan for wars is also affected by their culture, including geography. Island nations or those with long coasts have understood and invested heavily in sea power. In the case of Britain, its navy – tellingly called the Senior Service – has absorbed more resources and had much greater prestige over the centuries than its army. While paintings, poems, films and histories memorialise the great naval battles – Salamis, Lepanto, Trafalgar, Midway – when one navy destroyed another, the main strategic purpose of navies is to control the seas, and the highways hat criss-cross them, and prevent their enemies from doing so. Even today land communications are vulnerable to disruption, either man-made or natural; how much more so in the past before surfaced roads and railways?"