Adopted by international agreement in 1906, which became the standard radio distress signal?

In which country was Adolf Hitler born in 1889? Adolph Ochs, who bought The New York Times in 1896, got his start at a paper in which Tennessee city? Adolphe Adam's masterpiece is the music for which 1841 ballet, in which the title girl rises from her grave to dance? Who is Barney and Betty Rubble's adopted baby son? Adopted in 1929, the flag of which independent state includes the keys of heaven? Adopted in 1965, Ontario's flag features three of which leaves? Which Middle Eastern nation adopted a flag in 1980 with "Allahu Akbar" written 22 times along its stripes? Adopted in 1994, the flag of which African nation reflects its racial and ethnic diversity?