The Great Chicago Fire is started in an attempt by the Plumbers to destroy the Hands of Armageddon.
Mid-20th Century
Bellwood Elementary School holds it's first talent show 50 years before the events of the movie (wherein they hold their 50th Anniversary All Student Talent show).
1974
Maxwell Tennyson is rewarded with the title of "Bellwood Plumber of the Year".
Ben's parents tape their 'experimental theatre days', including mime and mask work.
Early 21st Century
Ben and his cousin Gwen go on a road trip, where Ben gets the Omnitrix, and learns about Max's history as a Plumber. Ben also learns about the Null Void. Presumably, these events are the same as Ben Prime’s summer.
The events of Ben 10: Race Against Time were originally canon to the Prime Timeline.[DM 1] As of Ben 10,000 Returns, it has been retconned into an alternate timeline with many changes to the story such as Eon now being alternate timeline version of Ben 10,000 instead of an alien, and Chronians and Chronia no longer existing.