When asked what you see above, most people, including veterans of other branches of the service, would say "A Tank". That would be a wrong answer. What you see above is a U.S. Army self-propelled artillery piece, namely an M109 Series Howitzer.
This gun is on display at the U.S. Army Heritage Center in Carlisle, Pa. Not terribly far (a mile or so) from the U.S. Army War College at the historic Carlisle Barracks, which dates back to the Revolutionary War.
The M109 series was first introduced in the early 1960's, and is still in use today! The M109 has a crew of six: the section chief, the driver, the gunner, the assistant gunner and two ammunition handlers. The gunner aims the cannon left or right (deflection), the assistant gunner aims the cannon up and down (quadrant). The M109A6 Paladin needs only a crew of four: the commander, driver, gunner and an ammunition loader.
This is the first display you will see when entering the parking lot for The Heritage Center. There are many other items on display, of course. The hours vary by season, and this gun is available for viewing 24/7 365, but you'll probably want to visit during daylight hours. Personally, I wouldn't show up at 2:00 AM after a night of drinking. I have also made this gun a Sight on Sighter.
LOGGING PASSWORD: On the informative sign North of this display (not shown in in the picture above, which was taken from the South side), in the extreme lower left hand corner, you will see the insignia for a U.S. Army entity. This insignia is mostly yellow in color. Your logging password is the first word in their motto, which consists of two words. Case does not matter here.