On this day in 1974, bombs devastated two central Birmingham pubs, killing 19 people and injuring over 180.
Police said they believe the Provisional IRA planted the devices in the Mulberry Bush and the nearby Tavern in the Town.
The explosions coincided with the return to Ireland of the body of James McDade, the IRA man who was killed in Coventry last week when the bomb he was planting blew up prematurely.
The two blasts were only seconds apart and happened at about 2030 GMT, when the bars were packed with mainly teenage drinkers.
Police attempted to clear both pubs, but the bombs went off only 12 minutes after a man with an Irish accent telephoned the Birmingham Post newspaper with a warning.
The first attack was in the Mulberry Bush, which is located on the ground-floor of the 17-storey Rotunda office block.
The second device exploded 50-yards (45.7 m) away in an underground bar, the Tavern in the Town.
Michael Willis, 18, was in the Tavern when the bomb went off.
"I was going to put a record on the juke box when there was an explosion.
"There were bodies everywhere and I had to clamber over them to get out - the screaming and groaning from the injured was terrifying," he said.
Many of the injured were ferried to nearby hospitals in taxis and private cars, and dozens of ambulances from all over the West Midlands were called in.
Assistant Chief Constable for West Midlands Police Maurice Buck said the carnage caused by the bombs was "disastrous and appalling". The final number of dead was 21.
Hugh Callaghan, Paddy Hill, Gerry Hunter, Richard McIlkenny, Billy Power, and Johnny Walker were found guilty in 1975 of carrying out the bombings.
But the so-called Birmingham Six were released after 16 years in jail when their convictions were overturned by the Court of Appeal in May 1991.
The real bombers have never been prosecuted.
Three detectives were charged with perjury and conspiracy in connection with the investigation, but their trial was halted in 1993 on the grounds of prejudicial media coverage.
On the 30th anniversary of the attacks in 2003, Gerry Adams, the president of the IRA's political wing Sinn Fein, said he regretted the bombings had taken place.
