On Martyr's Road in Downtown Cairo, the ghosts of Egypt's uprising haunt every single step. Following the terrible clashes which erupted here in November last year, the long thoroughfare leading east off Tahrir Square became an unofficial shrine for Egypt's revolutionaries; its walls transformed by street art into a mesmerising point of pilgrimage.
The murals, which included Banksy-style stencils depicting victims of the regime, clearly unsettled the Egyptian government – one evening in September, municipal workers arrived under the cover of darkness to whitewash some of the artwork.
But memories die hard on Martyr's Road, the unofficial name given by some activists to Mohamed Mahmoud Street and the long wall of the American University in Cairo which has now become a giant outdoor canvas.
Within hours, Egypt's industrious graffiti artists were back on their step-ladders, buckets of paint in hand and brushes at the ready.
"There is a feeling that Downtown Cairo and Tahrir Square is our land," said Ammar Abo Bakr, a well-known artist who was one of the first people back in Mohamed Mahmoud Street to try and undo the government's handy-work. "We need to say that this is our place, and we can write whatever we want."
The result, like much of the work which came before it, is spectacular – an open air "gallery of the people", which judging by the scores of camera-snapping Egyptians who can be seen paying homage every day, is fast becoming something of an unofficial tourist attraction.
In the manner of the Berlin Wall before it, where the East Side Gallery still features a famous mural depicting Soviet leader Leonid Brezhnev smooching Eric Honecker, a place of death and despair has been reclaimed and transformed into a promenade of iconoclastic beauty.
One of the first murals to take shape following last month's clean-up job featured a placid-looking painter being menaced by a devilish, club-wielding police chief, his fangs dripping with blood – a tongue-in-cheek sideswipe at the government's attitude to street art.
Further along, away from Tahrir Square, is an enormous mural dedicated to the 79 football fans who were killed during the Port Said stadium disaster earlier this year. That incident, which many Egyptians blamed on government security forces, triggered yet more rioting in Mohamed Mahmoud Street, one of the main roads leading towards the Interior Ministry.
Now, eight months on, every name of each supporter who died is preserved in paint on the American University's wall, along with the words: "Remember them."
Numerous other victims of state-orchestrated violence have been commemorated along the street. Alaa Abd el-Hady, a medical student killed during a military crackdown on protesters in December, looms large in a dreamy 12ft-high mural near the AUC entrance; Mina Daniel, an activist shot through the heart when soldiers attacked a Coptic demonstration in October last year, peers out at pedestrians from a series of stark black stencils; and then of course there's Khaled Saeed, the Alexandrian man beaten to death by police in 2010 who became a posthumous figurehead of the uprising.
"People have been visiting Mohamed Mahmoud like it is a shrine," said Ganzeer, an artist who hit the headlines last year when he was arrested for putting up posters advertising an anti-government demonstration. "It has become more important than the actual graves of the victims."
The consecration of Martyr's Street as a temple of revolutionary memory came alongside an explosion in street art which followed the downfall of Hosni Mubarak's regime. According to Sherif Boraie, the editor of a recently published book on Egyptian graffiti, street art was "hardly significant" before the revolution.
"The revolution started and was fought on the street," he told The Independent. "The art was a constant response and commentary on events as they unfolded."
Soraya Morayef, a blogger who has documented the rise of revolutionary graffiti on her website, Suzee in the City, agreed. Prior to the fall of Mubarak, she said, street art was "anonymous", an underground phenomenon carried out by an unconnected web of low-profile enthusiasts. "If artists tried to make graffiti, they were not only attacked by police but by citizens too," she said.
But now, she added, much of that is changing. "I think it's fantastic and proof that there has been a cultural revolution as much as a social revolution."
Under Hosni Mubarak, artistic license was often muzzled by the state. Film scripts were tightly vetted, book publishing monitored and theatre and film festivals brought tightly under the auspices of the Culture Ministry.
But one walk down Mohamed Mahmoud Street is enough to realise how the former dictator's demise unleashed an artistic genie which had long been bottled up. Galleries which may once have shied away from featuring graffiti have now opened their doors for exhibitions which showcase local talent. There is also growing international recognition too. Dokhan, a graffiti artist from Alexandria, is due to exhibit his work in Washington DC later this month, while earlier this year Ganzeer displayed his talents at an Arabic graffiti event in Frankfurt. "Because of the exposure and the magnificence of their work, they are in demand," said Soraya Morayef.
According to Caleb Neelon, an American artist who has written a history of urban graffiti, the outburst of creativity on Egypt's streets taps into a long and irreverent tradition of deploying spray cans to undermine power and authority. "Whether it's political message or imagery, name-based graffiti, or street art of any kind, there's always an implicit exhortation to freedom in it," he said.
Yet it also represents a continuing ideological fault line running deep beneath Egyptian politics.
Following last month's attempts to expunge the memory of Mohamed Mahmoud, graffiti artists were accosted by a group of ultra-conservative Salafis who objected to a series of templates caricaturing fundamentalist Muslims.
"They were saying it was against the Prophet Mohammad," said Ammar Abo Bakr. "But the artists were just making a joke about what the Salafists look like."
Graffiti has not always been the preserve of Egypt's liberals. Spray-painted reminders close to mosques often encourage women to wear the veil, said Soraya Morayef, or ask worshippers to perform the wudu – washing their hands before prayer.
But when it comes to much of the post-revolutionary artwork, it has often assumed a decidedly liberal overtone. "The artists were themselves the fighters and revolutionaries," explained Sherif Boraie. "Generally, there were few Muslim Brotherhood or Salafis and they are not known for open progressive artistic minds."