A railway tunnel beneath the Bosphorus Strait has created a new link between the Asian and European shores of Istanbul. There are already two bridges over the strait, but the tunnel should make the journey faster.
Work on the tunnel started in 2004, but archaeological excavations delayed constructions. The underwater section of the tunnel runs less than mile. Overall, it stretches more than nine miles.
The BBC's James Reynolds was one of the first people to travel inside the tunnel, and joins Here & Now's Jeremy Hobson.
This segment aired on October 31, 2013.