Many have commented that the 'Pen' resembles the U.S. Capitol when it's lit up at night. It has a wide block of front steps and a silver dome, but the similarities end with the razor wire and guardhouses. Prisoners from the U.S. Disciplinary Barracks at Fort Leavenworth helped with the first phase of construction in 1903. The penitentiary was completed in the mid-1920s, and although it was once one of the largest maximum-security prisons in the country it is now a medium-security federal prison to 1,800 inmates. Incarcerated here were such well-knowns as the 'Birdman of Alcatraz' Robert Stroud, George 'Machine Gun' Kelly, George 'Bugs' Moran, boxer Rocky Graziano, and drug trafficker Manuel Noriega. Visitors are not allowed on the grounds.