Answer: The stadium in Rome where over 100,000 people watched mock naval battles and gladiators fight was known as the Colosseum.
Step-by-step explanation:
This iconic amphitheater was built in 80 AD and is one of the most popular tourist attractions in Rome. It was used for various events such as gladiatorial contests, animal hunts, and mock sea battles. The Colosseum was able to hold up to 50,000 to 80,000 spectators and sometimes even up to 100,000 people in special events. It was also used for public spectacles that were free to attend, which made it an essential part of Roman culture and society.