The US Is Rebuilding the Airfields That Staged the Hiroshima Nuclear Strike

The War Zone has an article with more details, apparently this has been going on since late 2023:

https://www.twz.com/air/massive-wwii-b-29-bomber-base-fully-...

I’d like to know more about how the first WWII airfield was built. That had to have been a colossal effort.