One of van Gogh's most popular and widely known series are his Cypresses. During the Summer of 1889, at sister Wil's request, he made several smaller versions of Wheat Field with Cypresses.^[168] These works are characterised by swirls and densely painted impasto, and produced one of his best-known paintings, The Starry Night. Other works from the series include Olive Trees with the Alpilles in the Background (1889) Cypresses (1889), Cypresses with Two Figures (1889–1890), Wheat Field with Cypresses (1889), (van Gogh made several versions of this painting that year), Road with Cypress and Star (1890), and Starry Night Over the Rhone (1888). They have become synonymous with van Gogh's work through their stylistic uniqueness.