When a campaign plane carrying Republican vice presidential nominee Mike Pence skidded off the runway during a rainy landing at New York's LaGuardia Airport last week, no one on board was injured.
And for that, they can thank the airport's "arrestor bed," a block of lightweight, crushable cement designed to collapse under the weight of a plane in order to slow it down after it overshoots the runway.
You can find arrestor beds at the ends of more than 100 runways at U.S. airports including Boston Logan, Chicago Midway, and San Diego International.
Federal Aviation Administration guidelines call for safety areas that extend 1,000 feet beyond the end of each runway, but in airports—like LaGuardia—built before the standards were implemented, other solutions had to be found.
Hence Pence's rescue by crushable concrete.