You know when you come across a property and theres a Red Box with an "X" in it with the initials of the municipality's fire department on it?

Theyre all vacant. Im hearing theyre condemned properties. But i feel like because theyre condemned, these would be perfect...because no one wants them...or maybe thats a warning...."not even an investor would want this property". Has anyone messed around with a condemned property? If so, howd you go about acquiring it and demolishing, building on it?