Top contributor Bbloss created this stunning drone video of what may be the world's most expensive bridge. Following its partial collapse during the 1989 San Francisco earthquake, a decision was made to rebuild the eastern half of the landmark San Francisco Bay Bridge, which spans over 7 km (almost 4.5 mi.) over the bay. Construction on the eastern span replacement began in 2002 and wasn't completed until 2013, a six year delay. Its final coast was $6.5 billion, vs. an initial estimate of $250 million!