<http://schema.org/mainEntityOfPage>
<http://www.upi.com/Science_News/2014/04/22/NASA-calls-on-Earthlings-to-celebrate-Earth-Day-with-GlobalSelfie/7291398184369/>
<http://www.upi.com/Science_News/2014/04/22/NASA-calls-on-Earthlings-to-celebrate-Earth-Day-with-GlobalSelfie/7291398184369/?spt=tsb&or=1>