The Queen has laid a wreath at the Republic of Ireland's Garden of Remembrance during the first visit to the country by a British monarch.
The act is significant as the garden, in Dublin, is dedicated to people who fought for Irish independence.
Dozens of protesters gathered nearby amid one of the biggest ever security operations in the country.
Earlier, the Queen was welcomed by President Mary McAleese after flying into Baldonnel military airbase.
Earlier it emerged that a pipe bomb found on a bus bound for Dublin on Monday had been made safe by an Irish army team.
Upon landing at the military airbase, just outside Dublin, the Queen emerged wearing an outfit of symbolic emerald green.
The monarch later emerged from dinner wearing a white outfit.
God Save The Queen was played when she arrived at the Garden of Remembrance to lay the wreath - regarded as a highly symbolic act as the garden commemorates Irish people who fought over the centuries against British rule.
A one-minute silence followed the laying of the wreath, after which the Irish Tricolour was raised from half to full mast and the country's national anthem was played.
Meanwhile, riot police officers jostled with demonstrators at two separate protests on streets several hundred yards from the garden. BBC NEWS
