Other Academic Competitions - Urgent

[Great Bustard]

This is a bit of an odd and urgent request, but which non quizbowl-style academic competitions out there fulfill the following criteria:
1. Nationwide, but not global
2. Relatively high number of participants
3. Well-run, and fair competition within the structure of how it's set up
4. Have a designated national champion

If you know of such competitions, please list them in the thread below. This is very time-sensitive - I must have this by 2pm Eastern this afternoon. Basically, what I'm trying to do here is distinguish between what's more legit and what's less so within the whole universe of debate/Model UN/various science olympiads/other competitions, etc.
In particular, if people know of such competitions for humanities fields (English, art, music) other than the National Spelling Bee, please let me know. Obviously, I know of quite a few other competitions, but my personal experience is limited beyond the realm of quizbowl, so I'm looking for any advice here.

[Great Bustard]

As a follow up to this, does anyone know if any Americans (other than James Mullen for geography), won any of the international science olympiads this summer?

[RexSueciae]

We the People is a thing. I only know about this because its finals have notably conflicted with National History Bowl since 2012.

[Great Bustard]

Additional follow up - is there specifically any sort of national championship for Model UN or Model Congress?

[jonpin]

Academic Decathlon fits those criteria to the best of my memory.

[heterodyne]

I believe that Ocean Science Bowl meets these criteria, except for maybe the nationwide one. Not sure how widespread it is.

[Schmidt Sting Pain Index]

Academic WorldQuest and Envirothon fit the criteria

[The Polebarn Hotel]

Additional follow up - is there specifically any sort of national championship for Model UN or Model Congress?

There is no specific championship for Model UN as far as I know. All of the most important conferences are international.

[coldstonesteveaustin]

I've never done it, but maybe Science Bowl? Also, here is a map of the competition sites of Ocean Science Bowl (http://nosb.org/compete/regional-competition-map/); it's mostly states that have a coastline on either the Pacific, the Atlantic, the Great Lakes, or the Gulf of Mexico, plus Colorado.

[Harpie's Feather Duster]

You probably already know about it, but Certamen is similar to quizbowl in many ways but focuses on classics and Latin. Wikipedia indicates that it seems to have a NASAT-esque national championship.

I've also been told about Fed Challenge from some of my friends at the Indiana St. Joseph, it appears to have a national championship but also seems to be more similar to something like Model UN than quizbowl.

[coldstonesteveaustin]

You probably already know about it, but Certamen is similar to quizbowl in many ways but focuses on classics and Latin. Wikipedia indicates that it seems to have a NASAT-esque national championship.

Whoops, I totally forgot about this; I was on Team California for the advanced level this summer. The national tournament goes like this: three rounds of playoffs; each match has three teams; each round is 20 relatively short tossups with two related bonuses per tossup. Nine teams make the semifinal playoffs based on total number of points accumulated in the prelims, then the winners of each of the three semifinal matches make it to finals.

Distribution is 40% actual Latin grammar/vocab/listening comprehension/etc., 20% literature, 20% myth, and 20% history.

[jonpin]

He said NON quizbowl style, hence not Science Bowl or (from the sound of it) Certamen.

[coldstonesteveaustin]

So basically, things that don't involve buzzers?