Problem: What was worn by the leader of the first Tour de France?
Answer: green armband

Problem: What type of highly directional microphone, commonly used on television and film sets, in stadiums, and for field recording of wildlife, was invented by Fritz Sennheiser in the 1950s?
Answer: shotgun

Problem: In which year were both the Chernobyl and Challenger Shuttle disasters?
Answer: 1986

Problem: The first concrete-steel composite arch bridge in the USA that links the states of Nevada and Arizona by spanning the Colorado River is near which other man-made construction?
Answer:
hoover dam