Final answer:
The missing key event for the New Kingdom in the timeline is Egypt's military campaigns against the Hittites and others in Palestine and Syria, which included the famous Battle of Kadesh.
Step-by-step explanation:
The key event missing from the timeline of the New Kingdom era regarding military campaigns is the conflicts with the Hittites and other groups in Palestine and Syria. During the New Kingdom, especially under pharaohs like Thutmose III and Ramses II, Egypt expanded its territory and fought a series of battles in the Levant. The most famous of these is the Battle of Kadesh against the Hittites, which occurred around 1274 BCE. Egypt's engagement with other powers in the region, such as the Mitanni, also characterized this period of Egyptian history.
The Egyptian military campaigns in the New Kingdom period were pivotal in establishing Egypt as a dominant power in the Eastern Mediterranean. These military operations led to territorial expansions, diplomatic relationships, and even the first recorded peace treaty with the Hittites after the Battle of Kadesh. In constructing an accurate timeline of major civilizations in Egypt during ancient times, including the military feats of the New Kingdom is essential to understanding the power dynamics of the era.