River Facts

An earthquake on Dec. 16, 1811 caused parts of the Mississippi River to flow backwards.

During spring tides, a tidal bore called the Pororoca rolls up the Amazon River, creating a continuous wave up to 4 meters high that can be surfed for over 12 kilometers. The phenomenon is strongest between February and March when Atlantic tides push ocean water upstream against the river's flow.

When a speeding GMC truck crashed through a bridge fence and plunged upside down into Utah's Jordan River in 2014, Leo Montoya Jr. was the first person to jump in - then shouted at frozen bystanders until more than a dozen strangers waded in beside him. Together they physically flipped the submerged vehicle upright, held one boy's head above water, and got all three trapped teenagers out alive.

In 1982, Air Florida Flight 90 crashed into the frozen Potomac River in Washington. A rescue helicopter lowered a lifeline to the survivors clinging to the wreck. Passenger Arland Williams caught it and handed it to the stranger beside him. He did it again and again, each time to someone else. When the helicopter came back for him, he had slipped beneath the water. The bridge the plane struck now bears his name.