"Wherever we go, across the Pacific or Atlantic, we meet, not similarity so much as 'the bizarre'. Things astonish us, when we travel, that surprise nobody else"

The writer is noting that when individuals travel they usually discover things that are uncommon or unforeseen, which can be surprising and also even shocking. While individuals may not necessarily discover similarities in the places they visit, they often come across points that are outside of their typical experience or understanding. The term "strange" suggests that these points might be specifically unusual or uncommon, possibly even distressing or disorienting. Generally, the quote recommends the sense of marvel and discovery that can include travel, in addition to the possibility for running into the unforeseen.