54K views · 964 reactions | The French-German border is littered with as many as 500 underground sites used during World War I. Researcher Jeff Gusky explores them and finds a vivid record of the lives the U.S. and German soldiers who fought here led. Americans Underground | Smithsonian Channel Aviation Nation | Facebook

8.6K views · 231 reactions | Among the thousands of Yale students and alumni who fought in WWI were a group of undergrads who formed the country's first naval aviation unit, nicknamed “The Millionaires Unit.” As the U.S. entered the First World War, Yale considered it a duty to train future leaders by giving them a sense of patriotism, devotion, and sacrifice. | Yale University | Facebook