The west anchor span of the Tappan Zee Bridge, the only portion still standing, comes down in a task that is expected to take most of the day.
While some sections were previously lowered, the main span was imploded and dramatically crashed into the Hudson River with a resounding boom in January.
The controlled demolition went off without a hitch, when explosive charges safely detonated at the support columns on the bridge's east anchor span.
The new Mario Cuomo Bridge replaced the 64-year-old Tappan Zee, which was once a poster child of America's crumbling infrastructure.
The major thoroughfare spans the Hudson River between Tarrytown in Westchester County and Nyack in Rockland County about 30 miles north of New York City.
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