CAIN's coverage of The Dublin and Monaghan Bombing, 17 May 1974 shows how severe the Troubles could become in Dublin, and it may not be a "proper" war, but for those killed and maimed, I'm sure that was little consolation.

Dublin was also accidentally bombed by the Luftwaffe in 30-31 May 1941, here's some accounts of the bombing maintained by the Dublin City Archives showing that this bombing was quite a break from Ireland's neutrality.

At the start of the Civil War, the IRA Irregulars were in the Four Courts and had be dislodged by force by pro-Treaty forces on 28 June 1922. In addition to the lives lost (estimates vary), the Four Courts housed a lot of governmental and historical records such as the Irish Chancery Rolls that were lost in the resulting fires.

While Dublin may not have seen Stalingrad-levels of destruction in the twentieth century, it has seen its share of war and political violence that has killed and maimed many and destroyed portions of the city's historical and cultural heritage.

Dublin may not have been sacked in recent times but it changed hands by force many times in its early history. For example the suburbs were sacked by Robert the Bruce in 1315 and it fell to the Fitzgeralds during the Wars of the Roses. There were two unsuccessful sieges during the confederate wars in the 1640s.

London has not been occupied by a foreign power in over a 1000 years. Dublin, on the other hand, was invaded and conquered by the British during that period.

Malachy, High King of Ireland, and his ally Brian Boru, King of Munster, sacked Dublin, then a Norse city, in 999. Brian then took the mother of the Norse ruler Sitric Silkbeard, Gormflaith, as his wife, and restored Sitric to the throne.

I will edit later when I have more time to provide historical context.

Edit: Brian and Máel Sechnaill mac Domnaill, (or Malachy) had agreed in 997 to divide the island between them, with Brian ruling the southern half (Munster) and Máel Sechnaill the northern (Meath). They also agreed to fight together against the Norse in Dublin. At the time, the Norse had established cities around the coasts of Ireland such as Dublin, Limerick and Wexford, but had not encroached very far inland.

However, the Leinstermen, Irishmen from the southeast of the island, led by Máel Mórda, joined with the Norsemen and met the Muster/Meath army at the Battle of Glenmara in December 999, where they were routed with 7000 Norsemen slaughtered. This left Dublin wide open for Brian's forces, and he sacked and pillaged the town for a week from New Years Eve and into the new millenium.

This was a major victory for Brian, who was already sixty years old at the time, and he soon fell to war with his erstwhile ally the High King Máel Sechnaill, whom he defeated, and became the High King himself.