Three podcasts I enjoy listening to and learning from these days are Back Story, 99% Invisible, and Surprisingly Awesome.
Back Story takes on random, diverse American historical subjects such as money, Judaism, and the history of testing. Episodes are about 50 minutes. They change up the narrators, have music in-between, and generally make it very upbeat and energetic. They often feature a short conversation with a listener too! You can listen to some segments or the whole thing. Very entertaining! http://backstoryradio.org/shows/
99% Invisible is similar to BackStory in that they delve into topics such as Super Tall 101, Soul City, and The White Elephant of Tel Aviv, to name a few, that you probably don’t know anything about- and you always learn something. Episodes are about 22 minutes.
99% Invisible is about all the thought that goes into the things we don’t think about — the unnoticed architecture and design that shape our world. (http://99percentinvisible.org/about/the-show/)
The last “Who Knew?” podcast is Surprisingly Awesome from Gimlet media. https://gimletmedia.com/show/surprisingly-awesome/episodes/ Topics that you thought were boring because you really didn’t know anything about them turn out to be “Surprisingly Awesome!” Tune in and learn about Frequent Flyer Miles, Circle of Fifths, Adhesives, Broccoli, and Concrete, to name a few. Episodes are around 30 minutes. (Their intro music is the best!)