This was a piece of a B-52 that was shot down in 1972 that has been left as a historical vestige by the people of Hanoi, Vietnam.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/49502969231@N01">Colin Mutchler</a> from Brooklyn, United States
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/49502969231@N01/78727623/">b52 lake</a>