Now experts are painstakingly examining its thousands of pipes at the start of a multimillion-dollar restoration project that aims to turn the hall back into a cultural landmark, as part of the city's broader effort to revive downtown Johannesburg.

"It is one of the most beautiful organs I have seen, look at the wonderful woodwork," said Austrian organ builder and renovator Wendelin Eberle. "It's really a piece of art."

The organ was built in 1916 by famed British makers Norman and Beard, 30 years after the gold rush that spawned Africa's wealthiest city, one of just three of its kind in the world.

Designed to accompany a choir or orchestra, the organ transformed the colonial hall's West Wing into a cultural magnet for the rising city.

Over time, City Hall also suffered wounds from South Africa's violent history. The site of some of the earliest protest marches against apartheid in the 1950s, the building was the target of a bomb attack at its main entrance in 1988.

When democracy arrived in 1994, the hall became a voter education centre for the elections that brought Nelson Mandela as president.

As South Africa's crime rate soared to global highs over the last two decades, many business left their downtown towers for fresher northern suburbs, leaving the city centre to sidewalk vendors hawking their wares outside crumbling buildings.

The organ is the king

City Hall remains in use as the provincial legislature, but the organ hasn't been touched in six years, and Eberle said a 1974 modernisation that sought to update its neo-baroque sound may have done more harm than good.

"The arrangements were changed and things were mixed up," he said.

Petty vandalism has also scarred the organ, like the rest of downtown. Some of the pipes have been stolen, while others were damaged by rats, Eberle said.

Austrian embassy funding study

Faced with the pressing needs to fight still-crushing levels of poverty, unemployment and crime, South Africa's government has trimmed much of its cultural spending, but the Austrian embassy is financing Eberle's study to determine how to repair the organ.

"Cultural heritage preservation is worthwhile because it's your history," said Austrian ambassador Otto Ditz. "The organ is the king of all instruments — it can accompany the orchestra, but can be soft enough assist a vocalist."

The city is trying to turn the hall into a tourist attraction and a venue for cultural activities. Johannesburg has already seen some success in using theatres and music venues as anchors to revive downtown neighbourhoods

If the organ is fully restored, the Johannesburg Philharmonic Orchestra could make its home there, its conductor Michael Hankison said.

"The organ is like an orchestra, it also has different voices"

"Many choirs in the townships can't afford instruments, let alone hire an orchestra. The organ will be a lovely asset to them," he said.

A proper restoration will take about three years and likely cost millions of dollars, Eberle said.

The organ has thousands of pipes that are just millimetres wide, while the largest is at least 50 centimetres wide and 10 metres long. Just repairing and installing those would take six months, he said.

Eberle, who has travelled the world to build and repair organs, said Johannesburg's is a forgotten treasure.

"The organ is like an orchestra, it also has different voices," he said.

"There had been so much damage by people who didn't know what they were doing and tampered with the organ. As a result the instrument has been lost."

AFP