The “canal” in the Amazon that breaks the rules

Rivers often join together. They rarely split apart. If you’ve studied geography, or even just stared at a map for a decent amount of time, you’ll know that this is the rule. Little rivers join together to become big rivers, which join together to become even bigger rivers, which flow out into the sea. There are some small exceptions to this rule. Winding plains rivers commonly split and rejoin around islands. Some rivers split into many small branches as they reach the coast, forming a “river delta”. River deltas are often home to large cities, like Alexandria in the Nile Delta, Shanghai in the Yangtze Delta, and New Orleans in the Mississippi Delta. A select few lakes (like Wollaston Lake in Saskatchewan) drain in two different directions. And a few smaller rivers actually do split farther upstream, mainly small mountain creeks near continental divides. Still, rivers rarely split apart, almost never split far from their mouths, and definitely don’t, say, divert thousands of tons of…