Weighing more than 25 tons each, the five 504 foot (153.6 meter) long trusses of the San Francisco–Oakland Bay Bridge’s eastern span have each been dismantled and lowered onto a barge that takes them away for further disassembly. In the Feb 2016 video above, video journalist Mark Jones explained how this 1935 feat of engineering was being slowly deconstructed in an environmentally friendly way.

Below, a speedy time lapse video of the third truss, taken away in May 2016.

As of August 2016, the last truss of the old Bay Bridge is ready for removal. The new eastern span opened in September 2013.

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