From Ryszard Kapuscinski, in his speech Herodotus and the Art of Noticing:
Herodotus, however, besides being the first reporter, was also the first "globalist." Fully aware of how many cultures there were on Earth, he was eager to become acquainted with all of them. Why? He believed that the best way to learn about your own culture is by familiarizing yourself with others. For your culture will best reveal its depth, value and sense only when you see how it is reflected by other cultures, which can shed the best, most penetrating light on your own, and thereby help you understand it best by yourself.
What did he accomplish with his comparative method of confrontation and reflection? Well, Herodotus taught his countrymen modesty, tempered their self-conceit and hubris, their belief in their superiority and arrogance toward non-Greeks, towards all others. He told them, "You think that the Greeks created gods? No. As a matter of fact, you've appropriated them from the Egyptians. You say your structures are magnificent? Yes, but the Persians have a far better system of communication and transportation."
Thus Herodotus tried by means of his reportage to consolidate the most important message of Greek ethics: restraint, a sense of proportion and moderation.