Final answer:
Amphitheaters were built into hillsides, with an example being the Amphitheatre of Pompeii, which seated up to 24,000 spectators and highlighted the advanced engineering of ancient civilizations.
Step-by-step explanation:
Amphitheaters were built into hillsides and held between 15,000 and 17,000 spectators. This architectural feat was common in ancient civilizations, particularly during Roman times, when amphitheaters were used for a variety of public spectacles, including gladiatorial contests, dramas, and other forms of entertainment. One notable example is the Amphitheatre of Pompeii, which was built in 70 BCE and could hold up to 24,000 spectators. These structures showcased the advanced engineering skills of the era, utilizing arches and concrete to create massive public venues with excellent acoustics, allowing even those at the back to hear what was happening on stage. In addition to Pompeii, other historical sites like the Phoenician stadium near the Temple of Amrit, built in 1500 BCE, also featured seats carved into a natural U-shaped hillside, accommodating up to 11,000 people.