In the summer of AD 64 fire devastated a large part of central Rome. (Some blame Nero for setting the blaze intentionally, but fire was a real risk and a common occurrence.) The ashes of patrician palaces mingled with those of slums. Afterwards, anything in the area east of the Forum left unsinged was knocked down to make way for a home fit for the sun-god that Nero liked to think he was.
Work began on the emperor's Domus Aurea (Golden House) immediately after the fire had died down. A three-storey structure, its main façade faced south and was entirely clad in gold; inside, every inch not faced with mother-of-pearl or inlaid with gems was frescoed by Nero's pet aesthete Fabullus. Fountains squirted perfumes, and baths could be filled with sea or mineral water. In one room, Suetonius claimed, an immense ceiling painted with the sun, stars and signs of the zodiac revolved constantly, keeping time with the heavens. Lakes were dug, forests planted and a 35m-high (116ft) gilded bronze statue of Nero erected.
After Nero's death in AD 68, a damnatio memoriae was issued and work was begun to eradicate every vestige of the hated tyrant. Vespasian drained the lake to build his amphitheatre (the tight-fisted emperor kept Nero's colossus, simply putting a new head on it, and so the stadium became known as the Colosseum), and Trajan used the brickwork as a foundation for his baths. So thorough was the cover-up job that for decades after the house's frescoes were rediscovered in 1480, no one realised it was the Domus Aurea that they had stumbled across.
The frescoed 'grottoes' became an obligatory stopover for Renaissance artists, inspiring - among other things - Raphael's weird and wonderful frescoes in the Vatican (and also giving us the word 'grotesque'). The artists' signatures can still be seen scratched into the ancient stucco. After decades of restoration, some 30 rooms of the Domus Aurea reopened in June 1999 only to suffer a partial collapse after heavy rains in the winter of 2005. In February 2007 the Domus partially reopened for guided tours, which allow visitors a close-up look at the frescoes and plaster mouldings from high up on the restorers' scaffolding.