Birmingham pub bombings

The Birmingham pub bombings were carried out by the Provisional Irish Republican Army on 21 November 1974. Two bombs exploded in pubs in Birmingham, West Midlands, England, killing 21 people.
The first bomb exploded in the Mulberry Bush, killing ten people.
The second bomb exploded in the Tavern in the Town, killing eleven people.
A third bomb was planted in the doorway of a branch of Barclays bank. It was found by a policeman and did not explode. 
The Birmingham bombings were 20th century England's most deadly terrorist attack.