Sunday 30 January 1972 is remembered as arguably the most fatal – and significant – occasions during multiple decades of conflict in Northern Ireland.
In the streets of the incident – the legacy of the tragic events are visible on the buildings and embedded in public consciousness.
A civil rights march was organized on a wintry, sunny period in the city.
The protest was opposing the system of imprisonment without charges – detaining individuals without trial – which had been put in place after three years of violence.
Troops from the Parachute Regiment killed 13 people in the Bogside area – which was, and remains, a overwhelmingly republican population.
A particular photograph became particularly iconic.
Pictures showed a Catholic priest, Father Daly, using a stained with blood fabric while attempting to defend a crowd carrying a young man, the fatally wounded individual, who had been mortally injured.
News camera operators captured considerable film on the day.
The archive contains the priest telling a journalist that soldiers "appeared to fire in all directions" and he was "absolutely certain" that there was no reason for the gunfire.
That version of what happened was disputed by the original examination.
The initial inquiry determined the Army had been fired upon initially.
In the peace process, the ruling party set up a new investigation, after campaigning by family members, who said the first investigation had been a cover-up.
That year, the findings by the inquiry said that on balance, the paratroopers had initiated shooting and that not one of the victims had posed any threat.
At that time Prime Minister, the Prime Minister, issued an apology in the House of Commons – saying fatalities were "improper and unjustifiable."
The police started to examine the incident.
An ex-soldier, identified as the accused, was charged for murder.
Indictments were filed concerning the deaths of James Wray, 22, and in his mid-twenties another victim.
The defendant was further implicated of trying to kill multiple individuals, additional persons, Joe Mahon, Michael Quinn, and an unknown person.
There is a judicial decision protecting the veteran's privacy, which his lawyers have argued is essential because he is at danger.
He stated to the investigation that he had only fired at individuals who were possessing firearms.
This assertion was disputed in the final report.
Information from the inquiry was unable to be used immediately as evidence in the criminal process.
During the trial, the defendant was screened from view with a protective barrier.
He made statements for the opening instance in the proceedings at a session in December 2024, to answer "not responsible" when the charges were put to him.
Relatives of those who were killed on the incident journeyed from Londonderry to the courthouse each day of the case.
John Kelly, whose brother Michael was fatally wounded, said they always knew that attending the trial would be painful.
"I visualize everything in my recollection," the relative said, as we walked around the key areas mentioned in the trial – from the location, where the victim was killed, to the adjoining the courtyard, where James Wray and the second person were died.
"It even takes me back to my position that day.
"I assisted with my brother and lay him in the medical transport.
"I relived the entire event during the proceedings.
"Despite experiencing the process – it's still worthwhile for me."