Correct. One of the first great truly world power, between the 6th and 11th century, was a port in Indonesia (surprisingly). After that, Europe took the lead,

Correct. One of the first great truly world power, between the 6th and 11th century, was a port in Indonesia (surprisingly). After that, Europe took the lead, with Bruges, Venice, Anvers, Genoa, Amsterdam, London. US came after that with Boston, New York, California. Asia is now taking the lead again. The sea is a powerful ideology in itself. It brings you new goods, new ideas, change, desire to welcome strangers. It's also the place of nomadism, which was the normal way of living in almost all of human history. How do you produce "new" stuff ? By connecting "old" stuff in a "new" way. That's exactly what ports do, and that's probably why so many great empires emerged from them.