There is no way to "prove" any event from history. The historical method does not lend itself to "proof." "Proof" requires a controlled experiment that is repeatable in laboratory conditions. However, it is possible to provide enough evidence that all but the most recalcitrant skeptic must accept the findings.
For example, the explorers could take photos that are timestamped and gps'd. The explorers could take others up to the same location who could verify what was found. There is much evidence that could be put forward that the explorers have yet to provide. I am skeptical of this too. However, I am open to being convinced if enough evidence is put forward. I suggest a similar openness on your part.
It’s all George Bus..........