Just past the fourth circle of the canal near the north viaduct there is a place of utter darkness. No light can shine there and any torch brought in illuminates nothing more than the flame. It is said that those who step into the darkness rarely return and those that do are changed. Some say that there was once a time without the darkness but nobody claims to remember a time without it.
This poses quite a problem to those who wish to sail the sections of the river or canal that pass through the darkness. There exist skilled navigators who can guide a ship through the dark stretches of the water, some through years of practice and others through possession of senses beyond those considered normal by humans. However, at least a few ships that enter each week never come out again, and it is widely agreed to be a terrible nuisance.