It's funny, that moment when you catch a person realizing they're not where they're supposed to be. 

A well-to-do couple, judging by the looks of their SLRs and leather sandals, are enjoying a vacation in San Francisco. They are walking from Market Street with shopping bags in hand. After a block the man stops in his tracks, looks at his wife, then pulls out a map. This isn't the same district they were at five minutes ago.