Dublin Castle Ireland (1800–1922). After the signing of the Anglo-Irish Treaty in December 1921, the complex was ceremonially handed over to the newly formed Provisional Government led by Michael Collins. It now hosts the inauguration of each President of Ireland, and various State receptions. The castle was built by the dark pool ("Dubh Linn") which gave Dublin its name. This pool lies on the lower course of the River Poddle before its confluence with the River Liffey; when the castle was built, the Liffey was much wider, and the castle was effectively defended by both rivers. The Poddle today runs under the
Dublin Port Tunnel this eponymous and long-standing Irish company were bought by Mowlem before construction of the tunnel began. Thereafter, Irishenco was possibly best described as an Irish-based branch of Mowlem, which was itself dissolved in 2006. Dublin Port Tunnel The Dublin Tunnel (Irish: "Tollán Bhaile Átha Cliath"), originally and still commonly known as the Dublin Port Tunnel, is a road traffic tunnel in Dublin, Ireland, that forms part of the M50 motorway. The twin tunnels form a two-lane dual carriageway connecting Dublin Port, which lies to the east of central Dublin, and the M50 motorway at junction 2, close to Dublin Airport.