Anyway, it's back to science fiction this time:
Norah looked down at the waves lapping gently at the base of the wall. Here, it seemed rather prosaic – almost Earthlike – but there were other places along this wall's length where enormous waves, born from fathomless depths, smashed each day against the wall's foundations with more force than any wave that had ever been recorded back on Earth.
"How old is the Wall, Professor?"
"The Wall was built long ago. Those who built it would be like gods to us."
"Why did they build it?"
"No one knows."
Why would they build such a thing? What possible use could there be for a wall running the entire length of a planet's equator, restraining all of that world's oceans to its northern hemisphere? The magnificent majesty of it! The sheer arrogance to attempt a construct like this, and the staggering skill to actually do it.
Back on her ship, Norah wept. The Wall was beautiful. But the Prophet of Mars had spoken:
"Only God may remake worlds."
Norah pressed the detonator, and flew away without looking back as the oceans surged through a thousand breaches. God's will be done – but she'd remember the Wall intact.