The Panama Canal

A 40 mile constructed waterway connecting the Atlant and Pacific oceans, it takes 10 hours for the ship to cross from one side to the other. Before the canal, ships would have to travel an extra 8000 miles around Cape Horn (most southern part of South America), taking them around 2 months to complete
Around 25,000 lives were lost during the construction of the canal due to poor working conditions, malaria and yellow fever
$2 Billion in tolls is generated per year, a single toll for large ship can run up to around $450,000. The smalles toll was paid by an American Richard Halliburton in 19 he paid 36 cents to swim through the canal
It's a very easy and worthwhile visit to the canal from Panama City, just take a 20 minute Uber to "Miraflores Visitor's Center", this is the Panama Canal visitor center with exhibits, food & decks for watching ships pass through the locks