Watch Las Vegas: An Unconventional History: Part 1 - Sin City for Free: How to Stream the Movie Online at 123Movies. . Traces the often surprising, endlessly entertaining history of the country's most outrageous playground. Interviews with Las Vegas insiders as well as everyday citizens in search of the American Dream chronicle how Las Vegas transformed itself from remote frontier way station into the Depression-era "Gateway to the Hoover Dam," then into the mid-century gangster metropolis known as "Sin City," and finally into a family vacation destination and the fastest-growing city in the United States.