When visiting the complex of Bru na Boinne xI was impressed how well preserved the site was. It was not something I had expected from a site that old. I also learnt some interesting facts regarding the sites that are not normally mentioned:
1) The complex is the second largest concentration of neolithic art in the world (after the WHS Neolithic Orkney). As most of the art is presented on large stone slabs it is dubbed the largest concentration of megalithic art in the world.
2) One of the carvings presents a whale. I couldn't find any information as to whether whales lived in Europe at the time the site was built.
3) Almost all materials used in the construction of the site had to be transported from afar. Each material was transported from a different location. The furthest location had to be the Alps, which suggests that commerce on quite a large scale already existed in neolithic society. Closer links probably existed with Orkney, which also features evident cultural similarities.
4) The site consists of three locations, each with its own passage grave. Although the most visited one is Newgrange it is neither the largest nor the most impressive one. This honour belongs to Knowth. I would warmly recommend visiting both.
5) Unlike Knowth and Newgrange, Dowth is privately owned and at the moment cannot be visited. Work is underway for it to be opened to visitors.
6) Several unexcavated tombs can be seen in the area. Currently due to lack of funds there are no plans to excavate them.
7) Knowledge of the holy status of these tombs remained for thousand of years until the Christian period. The Romans paid their tribute in the form of a buried treasure next to Newgrange. In Knowth some signs of iconoclasm are visible. Four Christian kings of the 8th and 9th centuries had some of the slabs defaced and their names written on them for everyone to know.
I visited Bru na Boinne by public transport from Dublin. It is easy to take the train to Drogheda (30-60 minutes from central Dublin, trains travel about twice an hour). From Drogheda I took a taxi to the visitor centre (15 Euros each way). If you come early in the morning you will find a spot at tours for both Knowth and Newgrange. Funnily, sunny days see less visitors than rainy ones, said my guide.