Son Doong, the world's largest cave passage — big enough to fit a skyscraper — is deep inside a Vietnamese jungle. Exploring the dark caverns, home to beautiful rock formations and a river, takes ...

The curious minds at What If investigate living in a massive cosmic skyscraper, exploring life, gravity, and society in a city above the Earth. Enormous freshwater reservoir discovered off the East ...

What would it take to construct a building that reaches into space?