The last remaining tank

The ET-94 tank was one of three lightweight tanks NASA had ordered specifically for Space Shuttle Columbia. It was delivered to NASA in January 2001 and stored at the Michoud Assembly Facility.
Related slideshow: In Photos: Remembering the Columbia Space Shuttle Disaster 20 Years Later
Its predecessor, ET-93, was involved in the Space Shuttle Columbia tragedy that took place on February 1, 2003. The spacecraft disintegrated as it reentered through the atmosphere over Texas and Louisiana, killing all seven astronauts on board.