Awesome, awe inspiring modern ruins. Nothing comes close, not the Bronx, not Oakland. There are auto factories that cover square miles that have been deserted since the 1950s. There are 20 story hotels in the middle of downtown, there are shopping malls, there are entire streets. Sadly, a lot of it is now being demolished as a safety measure. A train station as large as grand central that hasn't seen a train in 35 years. Canals, factories.
Perhaps the Soviet Union has something similar. It's like Chernobal without the radiation. Chernobal might be safer to visit, all things considered.
Built for 2 million, now with 1 million. That's 1 million missing people that there is "stuff" there for. It's just a very strange feeling.
My wife visited a friend in Detroit last year, they actually sell t shirts saying I survived my trip to Detroit with a picture of an assault rifle on them. If this is a part of you city's tourism campaign then you are in trouble.