Final answer:
The highest award given during time of war in the U.S. is the Medal of Honor, with Staff Sergeant Ruben Rivers being one notable recipient. Other nations have equivalent honors, such as the Hero of the Soviet Union or the French Croix de Guerre.
Step-by-step explanation:
The highest award given during time of war in the United States is the Medal of Honor, which is awarded for personal acts of valor above and beyond the call of duty. Throughout history, this prestigious medal has been awarded to individuals who have demonstrated extraordinary heroism and bravery in combat. For instance, Staff Sergeant Ruben Rivers was a recipient of the Medal of Honor for his actions during World War II, an honor which was awarded to him posthumously in 1997. Additionally, during World War II, Admiral Chester Nimitz was promoted to Fleet Admiral, the highest-ranking officer in the navy, recognizing his leadership and service.
Other countries have their own highest military honors, such as the Hero of the Soviet Union awarded to Stalin or the French Croix de Guerre awarded to Jimmy Stewart. These awards recognize the valor and significant contributions of individuals and units during times of war.