Antique Real Photo Postcard, circa 1920s. Identified as Shadow Cave, Lost River, White Mountains, New Hampshire. Note the creepy horror film-style writing "Shadow Cave." Divided back, AZO stampbox, unused. Condition: This is an original photo postcard, not a copy or reproduction. It is in very good condition. Comments: The first documented exploration of Lost River took place in 1852. Similar to Alices tumble down the rabbit hole in Alice in Wonderland, local historian Elmer E. Woodbury wrote about how the Jackman brothers, Royal and Lyman, were fishing along the stream. The boys worked their way over and around the boulders when suddenly Lyman disappeared out of sight as if the Earth had swallowed him. Lyman had slipped into a moss covered hole and fallen into a cave about 15 feet below into a pool of water about waist deep. Now known as Shadow Cave, it was the first of the many caves the boys would soon discover.