There's something about being alone in a strange place that is rather exhilarating. Walking with tunnel vision, blocking out everyone around you, not understanding signs, people ignore you and leave you alone because why would they bother you? The more detached and bored you look the more people ignore you. It's pretty universal. I would feel the same walking in Lima as I would in Mumbai. Head down, eyes directly ahead, notice only limbs and make no eye contact.

Curiously enough I wandered into a ghetto in DC and was almost attacked by some random black dude. Friends had to hold him back because he wanted to attack me for no reason. I guess you can't always just fade away into the background -- sometimes the background won't let you.