An anti-art movement reactionary to WWI in that in a world that had ceased to make sense and be beautiful, art had to reflect that by ceasing to make sense and by ceasing to be beautiful.

In addition to the static artworks by Duchamp et al listed below, also check out the strong performance art from the likes of Hugo Ball and Tristan Tzara, heavily representative of Zurich Dada at the Cabaret Voltaire. Dada incarnated in different forms as Berlin Dada, Paris Dada, New York Dada and Neo-Dada.

DADA is a virgin microbe
DADA is against the high cost of living
DADA limited company for the exploitation of ideas
DADA has 391 different attitudes and colours according to the sex of the president
It changes -- affirms -- says the opposite at the same time -- no importance -- shouts -- goes fishing.
Dada is the chameleon of rapid and self-interested change.
Dada is against the future. Dada is dead. Dada is absurd.
Long live Dada.
Dada is not a literary school, howl.

-Tristan Tzara

From the "Dada Manifesto" 1918 and "Lecture on Dada" 1922. These works are believed to be in the Public Domain. CST Approved