The color associated with danger or warning is red. Red is often used in signs, signals, and alerts to indicate potential hazards or important instructions, as it captures attention quickly and evokes a sense of urgency. Examples include stop signs, fire alarms, and warning labels. This association might stem from red's visibility; it stands out in various environments, making it effective for communication. Additionally, many animals use red coloration as a signal of toxicity or danger, an aspect of nature that humans have mirrored in safety practices and design.