Had the same impression of Baltimore. So many beautiful old buildings just boarded up.i always have the same impression in the US. especially compared to the UK there's abandoned stuff everywhere. even in places i'd never expect, like collapsing houses close to the center of Miami for example. notice all this stuff upstate new york, vermont and so on. baltimore was kind of unbelievable for that stuff. i remember wandering around philly in about 2013 and coming across more abandoned housing than ever seen anywhere else. detroit obviously but that's a bit exceptional. i'm just listing places i've seen it.
really rare to find abandoned buildings in southern uk. i guess it's all too valuable. bits and pieces here and there but there's not much.
With america though its the odd building or strip here and there in other wise populated places. Rich seems to be finding entire abandoned complexes and neighborhoods.