Latest in investigation into missing US student

The video poses a question, 'What did a man?', which serves as the central theme for exploration.

What is the main topic introduced in the video?

• A historical event

• A scientific theory

• A philosophical question

• A mathematical problem

What is the key question explored in the video?

• Why is the sky blue?

• Where do we come from?

• How does gravity work?

• What did a man?