Built of pink-tinged marble in the 1st century AD, Verona's Roman amphitheatre survived a 12th-century earthquake to become the city’s legendary open-air opera house, with seating for 30,000 people. You can visit the arena year-round, though it’s at its best during the summer opera festival. In winter months, concerts are held at the Teatro Filarmonico. From October to May, admission is €1 on the first Sunday of the month.
The eighth biggest amphitheatre in the Roman Empire and predating the Colosseum in Rome, nothing of the incredible inside is visible from outside. Pass through the dingy ancient corridors, wide enough to drive a gladiator's chariot down, to re-emerge into the massive, sunlit stone arena, at least 50 levels of seating rising from the mammoth, oval showground. Note the amphitheatre is completely open so this is not a great place to visit in the rain.