Portrait Gallery’s Hide/Seek Uncovers an Intricate Visual History of Gay Relationships

There aren't many rumors that American socialite Wallis Simpson hasn't been subjected to. So here's how she actually infiltrated the British monarchy.

How Wallis Simpson Infiltrated British Royalty (4:18)

Whale milk is some of the richest milk available to any mammal. A baby whale will drink 150 gallons of it a day to sustain its dramatic growth.

Baby Humpbacks Need 150 Gallons of Whale Milk a Day (2:51)

The hagfish is a slime-emitting ocean-dweller that's remained unchanged for 300 million years--and it shows. It has a skull (but no spine), velvet smooth skin, and a terrifying pit of a mouth that's lined with rows of razor-sharp teeth.

The Hagfish Is the Slimy Sea Creature of Your Nightmares (3:00)

One highly influential ancient Middle Eastern civilization established some of the essential systems we still use today. Think you know which it is?

Who Decided to Put 60 Seconds in a Minute? (2:33)