This isn't just a travel thing. People who never met, separated by centuries and oceans, keep arriving at the same conclusions on their own.

In spiritual traditions there's an old idea called perennial philosophy — the claim that Buddhism, Taoism, mystical Christianity and the rest are saying the same core thing in different words. You see the same pattern outside of religion too. Newton and Leibniz worked out calculus separately, around the same time, without each other. Darwin and Wallace both landed on evolution by natural selection independently. Different lives, same answer, no copying.