The right of return is a principle in international law which asserts that members of an ethnic or national group have a right to immigrate to and become naturalized citizens of a country that they, the destination country, or both consider to be that group's homeland, independent of prior personal citizenship there. This belief is sometimes reflected in immigration laws that facilitate or encourage the reunion of a dispersed ethnic population. Why is the concept controversial in some countries?
Back in the day
Penicillin was the first antibiotic agent successfully used to treat bacterial infections in humans. Penicillin's effect on bacteria was first observed by biologist Alexander Fleming in 1928, but it was not until 1941 that scientists purified the substance and established that it was both effective in fighting infectious organisms and not toxic to humans. The first successful treatment occurred the next year. Where did scientists find the mold that allowed them to mass produce the drug?
Born on a day like today
Einstein was an intellectual giant of the 20th century whose name has become synonymous with genius. Recognized as one of the greatest physicists of all time, Einstein made countless important contributions to physics, including his theories of relativity, which profoundly revolutionized scientific and philosophical inquiry. In 1921, he received the Nobel Prize for his work on theoretical physics. Though he sought it for decades, Einstein never discovered a unified field theory, which is what?