Almost one hundred years ago, Robert Peary claimed to have made it to the North Pole by dogsled in thirty-seven days. Many doubted both the time and the method of conveyance.
Almost one hundred years later, a team led by Tom Avery replicated the feat in five hours less. They had a GPS and lots of documentation.
It can't be proved that Peary truly reached the North Pole, but it is now proven that it can be done. In that case, why would we doubt?
You can read more about it at the Ultimate North website.