The BBC's David Willey: "Visitors get a unique impression of ancient Rome"

Thirteen European culture ministers and the Italian president were on Thursday attending the historic opening of the underground palace, buried deep in the bowels of Rome's Palatine hills.

The 150-room ancient palace was known as Domus Aurea or Golden House because its walls were adorned with jewels and gold leaf.

Michelangelo and Raphael would lower themselves by rope to look at the frescoes

Archaeologists say the palace reveals a more aesthetic and intellectual side of Nero who was not only legendary for his bloodthirsty pursuit of early Christians, but who fiddled while Rome burned in the great fire of 64AD.

"This amazing palace was the image of Nero - novelty in the art of enjoyment, in games with light, painting and design and a whole new king architecture - he was a clever man," said archaeologist Silvia Cavazzini.

It was finished in 68AD, in the same year that the emperor killed himself.

The restoration however is still far from complete and only one-fifth of the rooms so far restored can be visited.

"We've done 1,200 square metres (4,000 square feet) out of a total 30,000 - there's a lot more to do, and we need around $30m to finish," said restoration work suprevisor Professor Adriano La Regina.

From Friday, tourists will be able to wander through a labyrinth of passages lined with frescoes that had all been covered by mould and calcium deposits.

The BBC's David Willey reports: "Modern classical scholars have rehabilitated his reputation"

BBC Rome Correspondent David Willey says that, for the first time, visitors will get a unique impression of ancient Rome in the first century of the first millennium.

The palace was buried under tonnes of dirt until 500 years ago when it was uncovered by robbers and then archaeologists who brought to light many important ancient sculptures.

Its discovery led Renaissance painters such as Michelangelo and Raphael to lower themselves down into the palace on ropes to marvel at the frescoes.

An extra $30m is needed to finish the restoration

Nero's biographer Suetonius wrote that the octagonal room at the centre of the palace had revolving decorations of ivory and wood and cloth hanging from the ceiling that showered its occupants with flower petals and perfume.

The opening of the palace is part of Italy's Millennium celebration plans to restore much of its significant ancient heritage.

Nero reigned from the age of 17 in 54AD to 68AD and built the palace from the ashes of the fire which destroyed much of Rome in 64AD.