H5N1 has led to the killing of 170 million birds. And the virus is mutating, risking a human pandemic.

The wood is so precious — and so expensive — that the French government heavily regulates its sales through annual auctions of oak forest plots. More from So Expensive Luxury winemakers ...

How did Lego go from a children's toy to a collector's item? And why is it so expensive? More from So Expensive Lego is the world's largest toy company, but it's gained a reputation for being an ...