First appearing in the 'Realistic Manifesto' (1920) by prominent Russian sculptor Naum Gabo, constructivism went on to play a major role advertising and more so in the use of propaganda (for example, best known being Mayakovsky's famous 1919 poster "Beat the Whites with the Red Wedge"). This links in with my previous discussion of post-war Bauhaus with Ludwig Hohlwein's use of propaganda in his work.
To focus on the architectural element of the movement, one of the most well known pieces of constructivist art (that never actually came to exist) is Tatlin's Tower, named after it's designer Vladimir Tatlin. The tower was intended to be situated in St. Petersburg in 1917 and 'dwarf' the Eiffel Tower in Paris, which itself stands at over a thousand feet, hosting Third International congresses annually. Geometrically-based, the tower was to be constructed with steel and contain multiple cylinders that would rotate, each at different speeds. The whole tower would take a full year to fully rotate and was considered to be a "giant" of architectural design and innovation. Another interesting element to the tower was that it was to be angled at the same angle which the earth is on it's axis, 23.5 degrees. Although the plans never finalised and the tower was never built, many replicas of a smaller scale were created to pay homage to it and the tower's design is now considered to be 'the' defining expression of construtivist architecture even though many quibble it's structural practicality.
I am a huge fan of constructivist architecture and believe that the world's cities wouldn't be half as advanced or recogniseable without this movement, especially with their innovations regarding skyscrapers and multi-story, glass buildings.