[Erik Latranyi]

Interesting. A canyon filled with liquid water is nothing special. But a canyon filled with solid water is!

Not really. Some fjords are frozen canyons winding their way to the leading edge of a glacier.

This one does not seem to have an outlet and is deeper.

[Oshkalaboomboom]

That deep below sea level should be warm enough to melt ice so I don’t think it could be completely solid.