Final answer:
When a national flag is flown at half-mast, it is internationally recognized as a symbol of mourning.
Step-by-step explanation:
When a national flag is flown at half-mast, it is internationally recognized as a symbol of mourning. This is done to show respect and honor for a significant loss or tragedy, such as the death of a national leader or a major disaster. Flying the flag at half-mast is a solemn gesture that is observed by many countries around the world.