On a hot, sunny morning in June 2006, Reginald Van de Velde was walking in the center of Sorrento, the famous Italian town on the Gulf of Naples, when something struck him. “I was walking on a footbridge to get back to my car,” says the Belgian photographer, “and noticed something unusual under the bridge.” Intrigued, Van de Velde leaned out over the bridge’s protective fence. “Then I saw it, this haunting ruin completely covered in vegetation.” Indeed, about 30 feet below Sorrento’s Via Fuorimura lies a deep gorge jacketed…