On December 12, 1910, 25 year old Dorothy Harriet Camille Arnold went out for a day of shopping in New York City. She was last seen walking down Fifth Avenue, and then she disappeared without a trace. Dorothy’s disappearance has sparked over 110 years of mystery and speculation.

Sources:
The Impossible Disappearance Of Dorothy Arnold from BuzzFeed Unsolved
The 100-Year Mystery of Missing Perfume Heiress Dorothy Arnold from The Daily Beast
The Girl Who Never Came Back from American Heritage
The Mysterious Case Of Dorothy Arnold, The Wealthy Socialite Who Vanished In Plain Sight from All That's Interesting