Final answer:
The State Tretyakov Gallery in Moscow holds a significant collection of Wassily Kandinsky's paintings, including some of his most important works like Composition VII.
Step-by-step explanation:
The most significant collection of Wassily Kandinsky's paintings can be found in the State Tretyakov Gallery in Moscow. Kandinsky was an influential Russian painter and art theorist who is often credited with painting one of the first purely abstract works. His works are celebrated and held in museums worldwide, but the Tretyakov Gallery holds some of his seminal pieces such as Composition VII. This gallery, along with the State Russian Museum in Leningrad, provides a comprehensive insight into Russian and Soviet paintings during the period of 1900 to 1930.
Moreover, the context in which Kandinsky developed his art was deeply influenced by his views on spirituality and art's relationship to the human soul. Despite the significant collection in Moscow, many of Kandinsky's works were dispersed during the early 20th century, especially after the Nazis held the notorious 'Degenerate Art' exhibition in 1937, which criticized and destroyed many modernist works.