Scientists and engineers at the Indian Space Research Organization (ISRO) monitor the Mars Orbiter Mission (MOM) in Bangalore, India on Sept. 15. MOM is expected to enter into Mars orbit on Wednesday. Jagadeesh NV /Landov hide caption

itoggle caption Jagadeesh NV /Landov

A plane flies over the Bardarbunga volcano as it spews lava and smoke in southeast Iceland on Sept. 14. The Bardarbunga volcano system has been rocked by hundreds of tremors a day since mid-August, prompting fears the volcano could explode. Bernard Meric/AFP/Getty Images hide caption

itoggle caption Bernard Meric/AFP/Getty Images

Students and teachers attend a rally during the class boycott at the Chinese University of Hong Kong on Monday. Thousands of students have braved sweltering heat to demand greater democracy for the territory. Tyrone Siu/Reuters/Landov hide caption

itoggle caption Tyrone Siu/Reuters/Landov

Syrian Kurds with their livestock wait behind a border fence near the southeastern town of Suruc in Sanliurfa province on Monday. Some 100,000 Kurds have fled from Syria into Turkey amid intense fighting between peshmerga forces and ISIS. Murad Sezer/Reuters/Landov hide caption

itoggle caption Murad Sezer/Reuters/Landov