Rome: Silhouettes of emperors, popes and artists are slowly emerging on the grimy walls of the Tiber River in Rome, part of an epic mural that tells the history of the Eternal City.

Technicians are using power houses on the dirty stone to stencil the 550-metre-long ‘Triumphs and Laments’, which is based on charcoal drawings by South African artist William Kentridge.

On display are Roman Emperor Marcus Aurelius, Italian dictator Benito Mussolini and the she-wolf who according to legend suckled the city’s mythical founders, Romulus and Remus.

Also among the silhouetted figures are the dead bodies of 20^th-century filmmaker and writer Pier Paolo Pasolini and murdered former prime minister Aldo Moro.

But organizers say the stenciled shapes will be allowed gradually to fade from view again as the grime slowly reclaims them.

‘The idea is to create an ephemeral work of art,’ the project’s technical director Gianfranco Lucchino, said on the riverside path. ‘The drawings ... will remain very temporary.’

Long delayed by bureaucracy, the mural project will be officially unveiled in April.

Up to 10 meters (33 feet) tall, on walls built to protect Rome from floods in the 1800s, the monochrome figures tell a story full of contrasts, Kentridge told Rome’s La Repubblica newspaper last month.

‘The Tiber is a river swollen with glory and pain. On one side the fortune of the popes, on the other the suffering of the Jewish Ghetto. Above ... a pulsating, splendid city; below, under the bridges, the desperation of the homeless,’ he said.

Tevereterno, the non-profit group organizing the project, hopes the art can help inspire and speed up urban regeneration.

Kentridge said he did not want to give people a history lesson, so the designs were not laid out in chronological order.

‘It is bit like putting a stethoscope on the banks of the Tiber and listening to the city tell its story,’ he said.

The frieze is due to provide the backdrop for a live shadow play and a brass band procession.