<http://schema.org/alternativeHeadline>
"Hundreds of 70-foot, bright yellow arrows once guided mail delivery pilots across the U.S., and many of them still exist today."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/wilderness-resources/stories/what-was-the-purpose-of-these-giant-concrete-arrows>