One of the most written-about Renaissance artists, da Vinci may also be among the most poorly understood.

Paris' centuries-old Louvre Museum — home of da Vinci's iconic Mona Lisa — is getting an $800 million makeover, and American visitors will have to help pay for it.

Excerpt: Once cherished by ancient civilisations from Egypt to Mesopotamia, lapis lazuli, often dubbed "blue gold," continues ...