'Exposition Universelle 1889' is based on the (6 month) Paris
Expo of 1889, and was inspired by the historical influence of
the Far East, specifically the 'gamelan' (which was showcased
during the expo).
European composers of the period (specifically Claude Debussy),
were impacted greatly by the unusual harmonic and rhythmic nuances
of the Eastern music they experienced.
As a result, 'Exposition Universelle 1889' is largely impressionistic
in style, with several underlying themes in the diametric keys
of B Major and D Flat Major, depicting the 'gamelan' (as a faster
more rhythmic theme), set against the impressionist style of the
late 19th Century.