Although buildings made of stone have a good chance of surviving the time scales required to create a good future tourist industry, even that is in doubt because of the use of substandard, standard concrete in modern America. But now the Japanese have invented ways to create concrete, essentially a form of liquid stone if you will, that lasts almost half as long as the classic Roman concrete. "We are still not as good as the ancient Romans, damn them, but this is good enough for us to build structures that will last long enough to be viable tourist attractions. I call on the patriotism of all true American construction firms to start using this new concrete in their work so that we can leave a legacy for our impoverished descendants."
The conference attendees were inspired by this announcements and also the breakthrough ideas in monument protection technologies and designs for future ruins that have the potential of enhancing tourist appeal. The conference attendees also voted to approve and issue a report describing the threat to future tourism dominance in a collapsing civilization and to propose possible countermeasures that have the promise of creating an important tourism industry for the failed and otherwise shamed former superpower.
Wikipedia page on Roman concrete