The Hermès Birkin prototype, originally made for Jane Birkin, sold at a Sotheby's auction in Paris for $10.1 million. What to know about the unique and coveted purse.

Sketched out on an air sickness bag, the first Birkin handbag — the prototype for fashion's must-have accessory — sold for a staggering 8.6 million euros ($10.1 million), including fees, on Thursday in Paris to become the second most valuable fashion item ever sold at auction.