1. Evolution. Remember that this stuff takes millions of years, so when a new intelligent species pops up, it's most likely that humanity's cities will be deeply buried under the earth. I see this as a great opportunity to add some depth to your world. Just imagine what kind of crazy theories their anthropologists would come up with! They will completely reinterpret mankind's place in the universe.
2. Scorched Earth. This has been done quite a few times, so if you're going to go with this route, it should either be insanely funny or insanely depressing. I believe that deeply emotional undertones can present an old concept in a unique light.
3. Reverse Engineering. What if an undeveloped new intelligent species discovered mankind's developments and ideas and reverse engineered them? Will it undermine this new species' ingenuity and philosophical cultivation because someone figured it all out for them?
4. Social Organization. Will these new species parallel mankind's social development? Will they traverse the same route: tribal communism-city states-feudalism/imperialism-capitalism/communism?
5. Genocide. Multiple intelligent species existing at the same time will undoubtedly try to wipe each other out. If they haven't already, you have a great tool for conflict in your world. What kind of epic heroes will emerge to save their dying people?
How to Destroy the World
1. Evolution. Remember that this stuff takes millions of years, so when a new intelligent species pops up, it's most likely that humanity's cities will be deeply buried under the earth. I see this as a great opportunity to add some depth to your world. Just imagine what kind of crazy theories their anthropologists would come up with! They will completely reinterpret mankind's place in the universe.
2. Scorched Earth. This has been done quite a few times, so if you're going to go with this route, it should either be insanely funny or insanely depressing. I believe that deeply emotional undertones can present an old concept in a unique light.
3. Reverse Engineering. What if an undeveloped new intelligent species discovered mankind's developments and ideas and reverse engineered them? Will it undermine this new species' ingenuity and philosophical cultivation because someone figured it all out for them?
4. Social Organization. Will these new species parallel mankind's social development? Will they traverse the same route: tribal communism-city states-feudalism/imperialism-capitalism/communism?
5. Genocide. Multiple intelligent species existing at the same time will undoubtedly try to wipe each other out. If they haven't already, you have a great tool for conflict in your world. What kind of epic heroes will emerge to save their dying people?