Which of the following was not a sports facility used in ancient Roman times?

The Hanging Gardens of Babylon is not a sports facility from ancient Roman times. This landmark is more closely associated with ancient Babylon, which is located in modern-day Iraq, and is famed for its extraordinary tiered gardens. The Hanging Gardens are considered one of the Seven Wonders of the Ancient World and, while they may have served various purposes, they were not constructed for sports events or activities.

In contrast, the Colosseum and the Amphitheater of Pompeii were specifically built in ancient Rome for public spectacles, including gladiatorial contests and other forms of entertainment. The Colosseum, in particular, is an iconic symbol of Roman engineering and hosted a variety of events that showcased thrilling athletic competitions.

The Stadium of Delphi, while also not a Roman facility, is related to ancient Greek sports and the Delphic Games, which were similar in spirit to the Olympic Games. It was a competition venue in ancient Greece rather than in Roman society.

Thus, the Hanging Gardens of Babylon stands out as being unrelated to the context of sports facilities relevant to ancient Roman culture.