"<span>the assassination of Archduke Franz Ferdinand" is thought to be the spark that lit the powder-keg </span>of war at the beginning of the 20th century. A dense web of alliances was set off from this shooting.
Answer: Aqueducts
Explanation: They were first developed around 312 B.C., these engineering marvels used gravity to transport water along with the stone, lead and concrete pipelines and into city centers. Aqueducts liberated Roman cities from reliance on nearby water supplies and proved priceless in promoting public health and sanitation.
The US government's decision to develop a hydrogen bomb, first tested in 1952, committed the United States to an ever-escalating arms race with the Soviet Union. The arms race led many Americans to fear that nuclear war could happen at any time, and the US government urged citizens to prepare to survive an atomic bomb.
The top 5% of the nation's wealthiest individuals received a third of the nation's income in the 1920's. The inequality towards work conditions, education and other social factors caused a great disparity in economic wealth during the 1920's. As a result only a few were benefactors of the nation's income during that decade.