Housed within the working General Post Office on O'Connell Street, the GPO Museum -- branded GPO Witness History -- tells the story of the 1916 Easter Rising from the very building that served as the rebels' headquarters. Patrick Pearse read the Proclamation of the Irish Republic from its steps, and the columned granite portico still bears bullet scars from the week of fighting that followed.
The exhibition uses film, sound, and original artefacts to set the rebellion in the context of the wider struggle for independence, and it is one of the best places in Dublin to grasp the events that shaped modern Ireland. Allow an hour or more, and step back outside afterwards to look up at the facade with fresh eyes.