Troops, police and ground-to-air missiles have been deployed ahead of Queen Elizabeth II's groundbreaking visit to Ireland.
Encouraged by the largely successful peace process in Northern Ireland, which has made her sensitive visit feasible, the queen will become the first British monarch to set foot in the Republic of Ireland. When a British sovereign last came, all of Ireland was still part of the United Kingdom.
The monarch's presence is still resented by some in Ireland who bristle at the legacy of British rule. Some have predicted violent street clashes or a terrorist attack.
Security measures being put in place Monday include a security detail to 8,500, armored cars, and air-defense systems.