Thomas Nast was called the "Father of American Caricature" according to his obituary in Harper's Weekly. His political cartoons helped expose the corruption of "Boss" Tweed and his political machine in New York City. One famous cartoon depicted Tweed with a bag of money saying "What are you going to do about it?" Even after escaping to Europe, Tweed was recognized and arrested by a Spanish official familiar with Nast's caricatures of the Boss, and returned to prison in New York.