Melted-and-refrozen snow plains mirror the sky until they look like ocean.

Evidence

We took neither of the trails, but cut right through the forest to a place where, through an opening in the Foot Hills, the Plains stretched to the horizon covered with snow, the surface of which, having melted and frozen, reflected as water would the pure blue of the sky, presenting a complete optical illusion. It required my knowledge of fact to assure me that I was not looking at the ocean. — Isabella L. Bird, A Lady’s Life in the Rocky Mountains, 263

Categorization

• CANDY: A frozen, glassy plain so convincing it takes deliberate self-correction to remember it isn’t water.