To protect themselves from chemical attacks in WWI, Canadian soldiers ingeniously used clothing soaked in what as primitive respirators?

Before WWI, what was the second most spoken language in the USA after English?

The Germans in WWI gave a fearsome all-black US regiment a memorable nickname. What was it?

In an attempt to mislead enemy pilots during WWI, the French military ingeniously constructed a replica of which major city near the actual one?

During World War I, in a wave of patriotism, what German food was temporarily renamed 'Liberty Cabbage' in the United States?

The demand for metal in World War I led to a decline in the popularity of which garment, paving the way for bras?

In an effort to promote patriotism during World War I, what common food did the U.S. government temporarily rename 'liberty sandwiches'?

What unusual event occurred between German and Allied troops on Christmas Day in 1914 during World War 1?

Tsar Nicholas II (Russia), King George V (Britain), and Kaiser Wilhelm II (Germany) were all first cousins. How were they related?

In what year did Germany finally complete the repayment of all its financial obligations and debts incurred from World War 1?