This clause is from a book that I'm reading called "日本人が知らない世界の歩き方". It's the first clause of the first sentence in the book and coincidentally the first one that I'm having trouble with. In particular, there are two things that I don't understand:
What does the を before 歩く mean? How is it possible for an intransitive verb to have an を particle? If this usage of the particle を is different than its usage as a direct object, can you please explain this alternate usage in depth?
What does it mean for のは to be preceded by a verb in the past tense? I understand that when の follows a present tense verb, it forms an infinitive or gerund (i.e. 歩くの = to run or running), but I don't understand what this means when it is applied to a verb in the past tense.
*edit: I just learned from the particle-wo tag that the particle can sometimes mean the course of a motion verb. So 外国を歩く means "walk around a foreign country" or "traverse a foreign country"? What English preposition is a good approximation for this particle? And is 歩く meant to literally mean "to walk", or is it a more general type of motion like "to traverse"?