Tourism in the Republic of Ireland on were built by them. As Dublin Airport is located just outside the city, most international visitors to Ireland begin their stay here. Among the main attractions in Dublin are Dublin Castle, the seat of British rule in Ireland until 1922, Phoenix Park, one of the largest inner city parks in the world, The General Post Office, one of Ireland's most famous buildings due to the 1916 Easter rising, Kilmainham Gaol, a former prison turned museum that held and executed the rebels of the 1916 Rising and Trinity College, where the Book of Kells and the Book of Durrow are
Easter Rising British soldiers arresting a woman who cheered the captured rebels. An RIC District Inspector's report stated: "Martial law, of course, prevents any expression of it; but a strong undercurrent of disloyalty exists". Thomas Johnson, the Labour leader, thought there was, "no sign of sympathy for the rebels, but general admiration for their courage and strategy". The aftermath of the Rising, and in particular the British reaction to it, helped sway a large section of Irish nationalist opinion away from hostility or ambivalence and towards support for the rebels of Easter 1916. Dublin businessman and Quaker James G. Douglas, for example,