Dublin's second-tallest storied building is either a modernist masterpiece or an unconscionable eyesore, depending on how you see modern architecture. It was built between 1961 and 1965 to replace the original Liberty Hall, which had been a hotel before it was taken over by James Connolly's Irish Citizen Army in 1913. Today it's the headquarters of the Services, Industrial, Professional and Technical Union (SIPTU), Ireland's largest trade union.
The original building also served as the HQ for SIPTU's predecessor, Jim Larkin's Irish Transport & General Workers Union – and so played a role in both the Dublin Lockout and the 1916 Easter Rising. Its replacement was originally fitted with non-reflective windows, but they were damaged by an Ulster Volunteer Force (UVF) car bomb in 1972 and replaced with the current reflective glass windows. The car bomb also put paid to the viewing platform, which had just opened but has remained closed ever since.