Yes, I'm also curious how creationism would explain all the remains of human predecessors we've found.

The history argument: The earliest huge cities (f.i. Nippur in Sumer) are about 7000..7500 years old. Why hasn't man invented writing, wheels, cities and kingdoms in the 192500 years before?

Simple answer: They were too few. Writing, wheels, cities and kingdoms became only necessary after the population reached a certain density. The Aborigines inhabited Australia since ten thousands of years, but hadn't ever changed their way of living. They just didn't need any cities or writings.

But early man left us other artifacts, like stone tools, and even artwork:

http://en.wikipedia.org/wiki/Venus_of_Willendorf