More than 50 world leaders arrived at Dublin's Convention Centre from 19 different locations, with arrivals staggered at 90-second intervals over two hours for security reasons. The unprecedented security operation in Ireland, named "Historic Goal," took two years to prepare. More than 5,000 police officers from Ireland, Northern Ireland, Latvia and Portugal are involved. Tactical commander Joe McLaughlin says the operation is going very well so far, but much work remains. #Ireland