The key to Dublin, as to many great cities, is its river and estuary. For trade comes with a river and a port with the sea. Gods of commerce and industry preside over Dublin's river at the Custom House, ships nudge their way to the traffic-lined quays, warehouses crowd on domestic dwellings. The river conditions the geographic consciousness of Dubliners. North and South of the river are metaphysical distinctions.
Streets have tops and bottoms.
A Dubliner, without sensing why, will know exactly what you mean. It's all based on the river.