This weekend marks the anniversary of an event that shook British politics to its very foundations.
The Phoenix Park Murders, on 6 May 1882, grabbed the attention of the world, when a secret assassination society - "The Invincibles" - targeted the Chief Secretary of Ireland and the Permanent Under Secretary as they walked along Chesterfield Avenue.
Today, a cross marks the spot in Phoenix Park but nobody is entirely sure who put it there.
Donal Fallon joins Gavan for another episode of Hidden Histories to discuss.