More than 500 events, ranging from guided tours and lectures, to music recitals, art exhibitions and historical re-enactments, have been scheduled for Heritage Week, which began yesterday.
The annual festival, which runs until next Sunday, seeks to "foster awareness of the built, natural and cultural heritage, thereby encouraging its conservation and preservation, and to raise interest in our shared European heritage."
Each county has its own programme of events with some sites offering free admission or reduced charges for visitors.
Co-ordinated by the Department of the Environment, Heritage and Local Government, the week is part of European Heritage Days, a joint initiative of the Council of Europe and the EU.
The EU states are due to take part in the scheme, along with 23 countries bound by the Council of Europe's European Cultural Convention, which this year celebrates its 50th anniversary.
In the North, European Heritage Open Days takes place next weekend, featuring free access to more than 200 public buildings, private houses, gardens, monuments and churches.
National Mill Day takes place in both the Republic and Northern Ireland next Saturday.Water Heritage Day, "dedicated to raising awareness of water as a unique part of our heritage", also takes place next Saturday.
For details of Heritage Week events call 1850 200 659, or see either www.environ.ie , or www.heritagecouncil.ie