Geography
Why River Capture Events Divert Drainage Basins Over Geologic Time
Quick fact
The Wind River in Wyoming is a classic example of an 'inverted' river: it still flows through a gap in a mountain range, but the river that once carved that gap has been captured and diverted elsewhere, leaving the gap 'wind gap' while the river flows through it.
Why this is interesting
Some rivers change course not by flood or human engineering, but by a slow 'theft' that can take millions of years. How can one river literally steal another's water?