The Panama Canal at Miraflores

The Miraflores Locks Visitor Center is fifteen minutes from downtown. Watching a container ship the size of a city block rise 27 meters in a lock built in 1914 is the most humbling engineering experience in the Americas. The museum tells the full story -- the French failure (22,000 workers died), the American completion (5,600 more), and the 2016 expansion.

Best time: Arrive by 9 AM for morning transits. Admission $20.