Bitonality is a musical technique that involves the use of two different keys or tonal centers simultaneously. This means that while one part of the music might be in the key of C major, another part could be in G major. This creates a rich and complex sound, allowing composers to explore new harmonic possibilities and emotional depths in their music. Composers like Igor Stravinsky and Béla Bartók have famously used bitonality in their works. By layering different tonalities, they create a unique tension and contrast that can evoke a wide range of feelings. This innovative approach challenges traditional notions of harmony and expands the boundaries of musical expression.