Students at South Korea 's Yonsei University threw more than just ordinary rocks at riot police -- some were samples that the geology department had taken 30 years to collect , newspapers reported on Friday .
<response> Students at <location>South Korea</location> 's <organization>Yonsei University</organization> threw more than just ordinary rocks at riot police -- some were samples that the geology department had taken 30 years to collect , newspapers reported on Friday . </response>