It was Owl who knew the history behind the underground city.

Over 700,000 workers were needed to build the underground city where he was buried.

To build this underground city, these guys had power we couldn't even imagine.

"Then how can we find out about this underground city?"

"They may tell the whole story of this underground city."

But the underground cities they built for their dead remain.

In winter, some 500,000 people use the underground city every day.

But also he learned the culture, the way things worked in the underground city.

"Have you ever been down to the underground city in Seattle?"

What better place to find the first people of the world than in an underground city?