Mary, indeed, it’s a fascinating street – originally known as “the spine of Buenos Aires” – because it’s the zero point for the streets that branch off it in opposite directions (all streets that cross Rivadavia change their names and reverse the counting of addresses in the opposite direction). Well, perhaps it is a worthwhile project to undertake – and I’ve certainly done other walks that were around 2 kilometers in length for writeups – so this could get broken into somewhere between 4-6 sections.