Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Smells hover just ...

He works in mysterious ways.

Examining the Seven Wonders of the World and explanations on why they were chosen and what is revealed about the builders who left them behind.

Smells hover just below our conscious awareness, conjuring up emotions and memories that shape how we perceive and navigate the world. An unexpected whiff of a long-forgotten snack or a dusty book can ...