Excerpts from Books and Wikipedia
"With a population of 27.5 million—approximately 56 percent Sunni and 43 percent Shi’ite—Yemen is plagued by grinding poverty, centrifugal political forces, and incessant terrorist activity. In the chaotic mid-2010s, an ongoing Shi’ite rebellion against the central government has destabilized the north even as a secessionist movement continues to gain ground in the south, where oilfields encourage such ambitions. Figure 6-17 highlights the geographic appeal of Yemen for al-Qaeda and other Islamic terrorist groups. Not only does Yemen lie at the back door of Saudi Arabia: its southern tip overlooks another of the world’s most crucial and busiest choke points at the Indian Ocean entrance to the Red Sea—the Bab-el-Mandeb (“Gate of Grief”) Strait—where ships tightly converge and run the risk of capture by pirates. Across the Gulf of Adan to the south lies another terrorist haven (and pirate stronghold), the failed state of Somalia, and just across the Red Sea to the west lies Eritrea, a likely target for extremists of the al-Qaeda stripe. The mass demonstrations of Yemen’s Arab Spring in 2011 against the 32-year-old regime of President Ali Abdullah Saleh led to his resignation . . . " [Geography: Realms, Regions, and Concepts, 17th Edition, p. 265-6]