The Leonard P. Zakim Bunker Hill Memorial Bridge (commonly known as the Zakim Bridge), opened to traffic in 2003. In the past decade, it has become an instantly recognizable feature of Boston's skyline.
Before the bridge opened, however, its engineering and construction had to be tested. In October of 2002, fourteen elephants (visiting from the circus) crossed the bridge to test its structural integrity. They all passed, safe and sound.
The "elephant test" was actually a common method for testing bridges in older times, due to the elephants' weight (naturally) and for their instincts — it was believed that they wouldn't willingly cross an unsound structure.
Lenny Zakim, after whom the bridge was named, was well known for bringing communities of different races, faiths, and backgrounds together.