Nero was a widely hated Emperor of Rome. He was accused of starting the great fire of 64AD that destroyed much of Rome's center. He declared the tragedy a perfect opportunity for his new palace to be built, atop the Aventine and Palatine hills. Around 200 acres of palace and gardens, with lake, waterfalls and 30 meter high bronze statue of himself at the palace entrance. The west and east wings were most likely mirror images of each other, with 140 rooms in each half. Revolving 11 meter high concrete made domed ceilings, most likely powered by the channeled movement of water, engineered to be spectacular and worthy of the opulent parties Nero likes to through during his time as emperor. Golden walls, glass mosaics, fine marble, baths, banquets, water falling along interior walls for effect, massive colonnades, perfectly manicured gardens and views of the city from high above. Once built, Nero declared: "Now I can begin to like like a human being!".
Needless to say, The Domus Aures is an incredible feat of engineering and a very important (albeit unhappy) part of the Roman Empire's history. Archaeologists continue to excavate and to find new corners of the palace, and have just recently (in 2016) opened the site back up to small, guided, hard hat, tours of the excavation. Available only for limited days of the week and only in the summer time (they may stop the tours soon, so make sure you go!).
Suetonius's excerpt describing Nero's Domus Aurea (written in 100AD):
In no other matter did he act more wasteful than in building a house that stretched from the Palatine to the Esquiline Hill, which he originally named “Transitoria” [House of Passages], but when soon afterwards it was destroyed by fire and rebuilt he called it “Aurea” [Golden House]. A house whose size and elegance these details should be sufficient to relate: Its courtyard was so large that a 120-foot colossal statue of the emperor himself stood there; it was so spacious that it had a mile-long triple portico; also there was a pool of water like a sea, that was surrounded by buildings which gave it the appearance of cities; and besides that, various rural tracts of land with vineyards, cornfields, pastures, and forests, teeming with every kind of animal both wild and domesticated. In other parts of the house, everything was covered in gold and adorned with jewels and mother-of-pearl; dining rooms with fretted ceilings whose ivory panels could be turned so that flowers or perfumes from pipes were sprinkled down from above; the main hall of the dining rooms was round, and it would turn constantly day and night like the Heavens; there were baths, flowing with seawater and with the sulfur springs of the Albula; when he dedicated this house, that had been completed in this manner, he approved of it only so much as to say that he could finally begin to live like a human being. Suetonius, The Lives of the Caesars