https://www.whiteeagleaerospace.com/first-flight-over-the-south-pole/

http://www.classichistory.net/archives/first-polar-flight

And somehow they accomplished this without compasses working. Which later proved problematic in 1979:

https://www.history.com/this-day-in-history/plane-crashes-over-antarctica

https://www.whiteeagleaerospace.com/first-flight-over-the-south-pole/

http://www.classichistory.net/archives/first-polar-flight