The Space Shuttle External Tank can be broken down into three main parts; a small tank holding liquid hydrogen (LH2), a larger tank holding liquid oxygen (LOX) and an intertank which joins the two sections together.
The LH2 tank shown in the photos is an early construction called the Ground Vibration Test Article (GVTA). This tank was fully assembled along with the LOX and intertank sections, and mated to the Pathfinder Orbiter (shown in a previous post, click here to view). This arrangement was placed inside the Dynamic Test Stand at NASA Marshall Space flight Center (shown in a previous post, click here to view) to test how the orbiter fit in the stand, which had just been expanded for the size of the shuttle. Then, the GVTA was mated to the Enterprise orbiter, and vibrated for hours to simulate launch.
The GVTA is now stored at NASA Marshall Assembly Facility in New Orleans, Louisiana. I covered the LOX GVTA in a previous post (click here to view)