Factbox-What do we know about Baltimore's Francis Scott Key Bridge?

(Reuters) - The 1.6-mile (2.57 km) long Francis Scott Key Bridge in Baltimore, Maryland, collapsed in the early hours of Tuesday after being struck by a container ship, plunging cars into the water.

Here's what we know about the Key Bridge:

* The Francis Scott Key Bridge spanning the Patapsco River is named after the author of the Star Spangled Banner, who was inspired to write the words in 1814 after witnessing the British defeat at the Battle of Baltimore.

* The 1.6 mile outer crossing of the Baltimore Harbor opened in March 1977 as the final link in I-695 (the Baltimore Beltway).

* Other structures along the route include a 0.64-mile dual-span drawbridge over Curtis Creek and two .74-mile parallel bridge structures that carry traffic over Bear Creek, near Bethlehem Steel's Sparrows Point plant.

* The bridge, at an estimated cost of $110 million, allowed for more traffic lanes and carried lower operating and maintenance costs than a tunnel.

(Reporting by Jyoti Narayan in Bengaluru; Editing by Nick Macfie)