Title: BeiDou Navigation Satellite System.
Question: When did China begin constructing the third BeiDou system?

Title: Modern history.
Question: Where did the depression cause negative effects?

Title: Marshall Islands.
Question: How many people lived in the Marshall Islands in 1960?

Title: Age of Enlightenment.
Question:
Why did Encyclopedias and dictionaries become more popular during the Age of Reason?