During more than three decades of Hosni Mubarak's rule, the walls lining Cairo's streets stood in stark silence, obscuring from view arbitrary detentions, torture and countless other human rights violations.
But after his ousting in early 2011, some of the walls became a canvas for popular expression as artists inspired by the "25 January Revolution" unleashed a creative uprising of their own in an area near Tahrir Square, the main focal point of the protests.
Ever since, the capital's Mohamed Mahmoud Street - one of the main arteries leading from the Interior Ministry into Tahrir Square - has effectively become an open-air gallery showcasing street art about a wide range of social issues.
Graffiti became increasingly popular after the "25 January Revolution", and colourful murals began to appear across Cairo. Mohamed Mahmoud Street has become the centre of this activity. Its walls depict a plethora of the issues still affecting daily life in the new Egypt - the more than 12,000 unfair military trials of civilians, the battle against the sexual harassment of women, and abuse by the security forces of peaceful protesters.
It has also become a bitter reminder of the need for accountability for the 17-month rule of the military council that replaced Mubarak. During this period more than 120 protesters were killed as a direct result of unnecessary and excessive use of force by the security forces - more than 50 of them on Mohamed Mahmoud Street itself.
For six days starting on 19 November 2011 Egypt's riot police, the Central Security Forces (CSF), violently suppressed protests in Mohamed Mahmoud Street, leaving 51 people dead.
The protests started after the security forces violently suppressed a sit-in of those killed or injured in the uprising in nearby Tahrir Square. Clashes erupted and images of dead bodies of protesters left on a pile of refuse were aired on television. Protesters flooded into Tahrir Square and nearby Mohamed Mahmoud Street.
At the time, Amnesty International blasted what it called a "brutal and heavy-handed response to protests [that] bears all the hallmarks of the Mubarak era".
The paintings that sprang up in the wake of that violence took on an ever-deeper significance for Egyptians, as they criticized the then-ruling Supreme Council of the Armed Forces for ongoing abuses and clamoured for change as elections approached.
Today, they are a reminder of how little has changed, and how much needs to be done to hold the security forces to account. Despite the scale of the violence, only one CSF officer is facing trial. Meanwhile, 379 protesters are being tried - it remains to be seen whether they will benefit from a recent presidential amnesty.
Although the Egyptian authorities have on several occasions attempted to paint over the murals, many remain as a testament to the tumult and triumph during and after the "25 January Revolution", as well as a memorial to the dozens who were killed in Mohammed Mahmoud a year ago.
"The concrete barriers along Mohammed Mahmoud Street were meant to block freedom of assembly. Today, they serve as a whole new outlet for freedom of expression - the creative criticism of the authorities," said Hassiba Hadj Sahraoui, Deputy Programme Director for the Middle East and North Africa at Amnesty International.
"A year after the protests that left such a deep impact on Egypt, many of these colourful murals remain not just as a memorial, but as a vital chronicle of the historic changes still taking place in the country. They serve as a daily reminder that the events of November 2011 still need to be addressed - and the need for accountability for the abuses of the Supreme Council of the Armed Forces."