Twenty years since the September 11 attacks, hundreds of undocumented workers who joined the clean-up efforts at Ground Zero are suffering from health issues caused by inhaling contaminated dust, with many still fighting to obtain US citizenship.

A trial on the 2015 Paris terror attacks is getting underway. Although it is likely to run over many years and most of the defendants won't be there, it may help survivors to better live with the trauma.

France is beginning to relive the atrocity that changed French life forever. The trial of 20 men over the terror atrocities of November 13, 2015 has begun in Paris. One of the accused was actively part of the attacks that night. Salah Abdeslam spoke in court to say he was a fighter of the Islamic State group. It is the most he has said since his 2016 arrest in Brussels.

The relatives of victims of the 9/11 attacks read out a list of names during a ceremony at ground zero in New York, 20 years after the terror attacks took place.

"Here, in this place, the name of God was dishonored," Pope Francis said at a Holocaust memorial in Bratislava. During World War II, Slovakia was governed by a Nazi puppet regime, headed by Catholic priest Jozef Tiso.

In this edition, hundreds of Gabonese peacekeepers are being withdrawn from CAR following the latest sex abuse allegations. Gabon says that the most recent accusation is exceptionally serious. Also, dozens of civic groups in Uganda have been suspended. Many human rights workers say it is part of a pattern of repression. And, South Africa’s largest rhino breeder is pushing to sell horns he trims legally off his animals to keep poachers at bay.

Relatives of the Afghan family killed after their father was falsely identified by the US military as a terrorist say they want a face-to-face apology and reparations.

About 6.8 million people took part in an earthquake drill in Mexico City as part of a civil protection exercise and to remember the victims of the 1985 and 2017 earthquakes.

Shocked and grieving Russians gather outside a university in the city of Perm after a student went on a campus shooting spree, killing six people and wounding dozens more. With a heavy police presence around Perm State University a day after the killings, they lay red carnations and light candles at makeshift memorials.

This week on The Observers, we start with the story of Ethiopian migrants who have been kept in Saudi Arabian prisons for months in poor conditions, with dirty surroundings and little to eat or drink. We spoke to Arafat Jibril Bakrii, a human rights activist who has been helping migrants to share photos and videos of their living conditions.

The World Health Organization again apologises to the victims who suffered rape and sexual abuse by workers sent to fight Ebola in the Democratic Republic of Congo from 2018 to 2020.

Pope Francis expresses his personal shame and that of the Church at the sexual abuse of children by French Catholic clergy, and offers the victims his prayers, after the scale of the problem was laid bare in a devastating report. An independent commission revealed earlier this week that French Catholic clergy sexually abused around 216,000 minors over seven decades since 1950, calling the scandal a "massive phenomenon" that was covered up by a "veil of silence".