In 12th century England, two children were found lost in a forest. They spoke only gibberish, wore strange clothing and had bright green skin. When the children finally learned to speak English, they described where they were from. And that's why, after almost 1,000 years, people still talk about The Green Children of Woolpit.

In 1828, a teenage boy was shuffling through a public square in Nuremburg. He seemed confused and disoriented. He had trouble walking and speaking. When police finally approached him, he was holding an envelope containing two letters. And those letters sparked the mystery of Kaspar Hauser.

In April 1922, in Brittany, France, 2-year-old Pauline Picard went missing. A massive search turned up nothing. The family was losing hope. A month later, Pauline was found wandering around a village over 200 miles away. Though her parents were overjoyed to have her back, they soon realized something wasn't quite right with their daughter.

These are three unsolved cases of the most mysterious children in history.