Before Neil Armstrong and Buzz Aldrin knew they would be the first to walk on the moon, they took crash courses in geology at the Grand Canyon and a nearby impact crater that is the most well-preserved on Earth.
![](https://3c1703fe8d.site.internapcdn.net/newman/csz/news/tmb/2019/5-beforemoonla.jpg)
Source:
https://phys.org/news/2019-07-moon-astronauts-geology-arizona.html