For a very different sightseeing trip on tours of Ireland try Belfast Zoo.
It is situated on a superb elevated site that affords fantastic views over Belfast as you walk around.
It is also close to Belfast Castle and Cave Hill.
The Zoological Gardens is home to over 140 types of animal , many of which are under threat in their natural habitat.
The Zoo carries out important conservation work and takes part in European and International breeding which help to ensure the survival of many speciaes under threat.
Worth a look on Belfast tours or even when stopping in Belfast on Ireland tours.
Even if you are visiting on a cruise ship this is a bit of a hidden gem close to the port.
Ireland Luxury Tours can arrange suitable trips.