Dublin is divided by the River Liffey. On the north side of the Liffey is O'Connell Street--the main thoroughfare, which is intersected by numerous shopping streets, including Henry Street and Talbot Street. On the south side are St. Stephen's Green, Grafton Street, Trinity College, Christ Church, St. Patrick's Cathedrals, and many other attractions.
Customs House on the Liffey
Dublin postcodes range from Dublin 1 to Dublin 24. As a rule, odd numbers are given to areas north of the River Liffey, while even numbers are given to areas south of the river. Usually, the lower the postcode, the closer to the city centre.
If you're already in the city, the main tourist office, located in St. Andrew's Church just off Grafton Street in the city centre (Dublin 2), is a good place to start for information. You can book accommodation and tours there, as well as find general information on where to go and what to do.
Although some of Dublin's finest Georgian architecture was demolished in the mid-20th century, a remarkable amount remains. They were a reminder of the past British imperialism and were pulled without regard to their beauty and architectural significance. They were replaced with modernist or pastiche office blocks, St. Stephen's Green (Dublin 2) being a prime example. Thankfully, attitudes have changed significantly, and Dubliners are now rightly proud of their impressive buildings from all eras.