Since i'm not going to teach you how to make rings (there are other instructables on that subject), wire,mandrels, and cutters will not be on this list.
24,000 (give or take 2,000) 1/4 inch, 16 gauge galvanized/ungalvanized rings (you can use other sizes/gauges but the number of rings will vary)
2 pliers (one for each hand)
PATIENCE! - putting 24,000 rings together is no small thing...it can take months, even years depending on your speed
Knowledge of how to make 4-1 European chainmail
This instructable teaches the basic principles of how to make chain mail rings and how to connect them using European 4-1:http://www.instructables.com/id/European-4-in-1-maille-chainmail-speedweaving/