Prior Recent 400th Anniversaries.
Note: Content will deal with more than New England

1 Get the firsts (Maritime provinces - several, Roanoke, Popham, ..., California, the interior (to wit, St. Louis, ...) -- See Gorges' remarks in the Annals about who was first
2 Find out about, and include, their celebrations
3 Then bring in New England's huge list

See for additional information.