Almost everyone knows that Wisconsin's state animal is a badger — hence the Badger State nickname. But, did you know that the state has a host of other official symbols? There's an official tartan ( ...

3. Galena A lead-based mineral, galena is often admired for its shiny, cubic structure. While it looks harmless, galena contains lead sulfide, which is toxic if inhaled or ingested. Long-term ...

The Romans invented concrete, aqueducts, and the basis of the modern calendar. But their achievements could have been even ...