Few Dubliners are aware that a former yard behind the castle – the site of the Black Pool or Dubh Linn from which the city gets its name has been turned into a garden with the new Chester Beatty Library of Oriental Art to one site and the converted stables to the other. Visitors are usually surprised an delighted by the colourful artworks scattered around the garden – colourful ceramic tiles at the bird bath, a giant glass snake, the memorial to the 2003 Special and the bust of campaigning (and murdered) journalist Veronica Guerin, immortalised by Cate Blanchett in the film "Veronica Guerin". The central area of the gardens is surrounded by wooden benches sporting a low-key Ogham design (Ogham being the ancient Irish system of writing), while the grassy middle part is interrupted by a Celtic design formed by paving stones. This is only really visible from the air – and actually is used as a helicopter landing pad on occasion. There is a further surprise in the form a a memorial garden dedicated to all deceased members of An Garda Síochána, the Royal Irish Constabulary and the Dublin Metropolitan Police.
On Saturday, 15 May 2010 the Taoiseach, Mr. Brian Cowen TD officially opened the Garda Memorial Garden at the Dubhlinn Gardens, Dublin Castle in the presence of the Garda Commissioner, Mr. Fachtna Murphy, the Minister for Justice, Mr. Dermot Ahern TD, and representatives of the families of the 83 gardaí whose names appear on the Roll of Honour and who were killed in the service of the State. The Memorial Garden honours the members of An Garda Síochána who were killed in the service of the State. The names of the members of An Garda Síochána who were killed are inscribed in stone within the garden. Additionally, a specially commissioned glass sculpture commemorates the sacrifice of the families left behind and a specially commissioned stone sculpture is a tribute to all deceased members of An Garda Síochána, the Royal Irish Constabulary and the Dublin Metropolitan Police.