Complex sentence: The Villa Mairea was designed for Harry and Mairea Gullichsen, to whom Aalto was introduced in 1935 by Nils-Gustav Hahl, who was keen to promote his bent-wood furniture designs.
Split into simpler sentences: The Villa Mairea was designed for Harry and Maire Gullichsen, to whom Aalto was introduced in 1935, by Nils-Gustav Hahl. Hahl was keen to promote his bent-wood furniture designs.