The World's Shortcut: How the Panama Canal Works [video]

One of the surprising things about the Panama Canal is how the sea level can differ between the Atlantic and Pacific sides. This depends not just on tides but on salinity, weather, and even differences in gravity. The Panama Canal has locks to lift and lower boats through the central lake, but even if the entire canal was built at mean sea level, it would still need locks to accommodate the (ever changing) difference between Atlantic and Pacific sea level at any given point in time.

Due to climate change, there are now many shortcuts across the Arctic in the summertime.

If this is the video I'm thinking of (I can't watch it at the moment), on the "Half as Interesting" (?) channel, I'd suggest checking out the other videos on this channel as well as the "Wendover Productions" channel (both by the same guy, AFAICT) if you found this one interesting.

I just discovered these two channels in the last week or so and there's a lot of interesting (to me) videos on them.