Ask: why some neighbourhoods feel more lively/alive than the others

Long time back I had seen a lecture video (black and white on youtube, don't remember exactly but was pretty lengthy) about why some neighbourhoods feels more lively/alive than the other, I am not able to find that anymore. By any chance anyone here is aware of what i am referring to, it'll be great if can provide me any additional detail that'll help me find that masterpiece.