Domus Aurea, Rome

Said to have been 25 times larger than the Colosseum at the height of Nero's reign, it took 15 years of restoration work before the remaining rooms of this immense palace were opened to the public. The interior is rich in walls covered with frescoes, gold, gemstones, and mother-of-pearl, and ceilings tiled in ivory, with openings for creating a shower of flowers and perfumes. After Nero's death, his successors attempted to eradicate his memory and eliminate every possible trace of this palace; fortunately for history this remained. Reservations are necessary, see official tourism website for details. Of the many masterpieces unearthed here was the famous Laocoön statue now on display at the Vatican Museums .