The 21st (twenty-first) century is the current century in the Anno Domini era or Common Era, under the Gregorian calendar. It began on 1 January 2001 (MMI) and will end on 31 December 2100 (MMC). Marking the beginning of the 21st century was the rise of a global economy and Third World consumerism, deepening global concern over terrorism after 11 September 2001, terrorist attacks and increased private enterprise. The NATO interventions in Afghanistan and Iraq of the early 2000s and overthrowing several regimes during the Arab Spring of the early 2010s led to mixed outcomes in the Arab world, resulting in several civil wars and political instability. The United States has remained the global superpower, while China is now considered an emerging superpower.