On this day 50 years ago, Zeppelin were about to kick off their 1972 North American tour at the Cobo Arena in Detroit. Like many of you, this is one of my all time favorite tours of theirs. Arguably the last time that all four members of the band were at or near their peak at the same time. For those who were old enough to attend a show or just remember that time in general, what are your memories of the tour? And what are everyone's favorite shows/moments from the tour?