The Flegreo Archaeological Complex region is believed to be an area of the first Greek settlement, known as the ‘Burning Fields’. The district is characterised by volcanic features with craters and other areas eroded by the sea and the elements. There are a variety of colours here due to the lush vegetation and over the years it has been a popular destination for academics and travellers interested in Greek and Roman history. The Flavio Amphitheatre, which dates from the era of the Emperor Nero, could hold up to 20,000 spectators and the underground sections of the structure are well preserved.