Final answer:
The significant Homo heidelbergensis finding in Schöningen, Germany, was the discovery of the world's oldest known wooden spears, evidencing early hafting technology.
Step-by-step explanation:
In Schöningen, Germany, the particularly significant Homo heidelbergensis finding was the discovery of the earliest known spears dated to about 400,000 years ago. These wooden spears were a remarkable technological achievement of the time, showcasing the use of hafting technology, which represents one of the first instances where humans created tools by combining different materials. In addition to stone tools, these spears likely aided in hunting and provided insights into the cognitive skills of H. heidelbergensis, such as planning and strategy.