After studying with the great Flemish landscape masters, he developed his technique to paint outdoors. Back in Spain, Haes took his students with him to paint in the countryside; under his teaching the "painters proliferated and took advantage of the new railway system to explore the furthest corners of the nation's topography." In the United States, the Hudson River School, prominent in the middle to late 19th century, is probably the best-known native development in landscape art. These painters created works of mammoth scale that attempted to capture the epic scope of the landscapes that inspired them. The work of Thomas Cole, the school's generally acknowledged founder, has much in common with the philosophical ideals of European landscape paintings — a kind of secular faith in the spiritual benefits to be gained from the contemplation of natural beauty. Some of the later Hudson River School artists, such as Albert Bierstadt, created less comforting works that placed a greater emphasis (with a great deal of Romantic exaggeration) on the raw, even terrifying power of nature. Frederic Edwin Church, a student of Cole, synthesized the ideas of his contemporaries with those of European Old Masters and the writings of John Ruskin and Alexander von Humboldt to become the foremost American landscape painter of the century. The best examples of Canadian landscape art can be found in the works of the Group of Seven, prominent in the 1920s. Although certainly less dominant in the period after World War I, many significant artists still painted landscapes in the wide variety of styles exemplified by Edvard Munch, Georgia O'Keeffe, Charles E. Burchfield, Neil Welliver, Alex Katz, Milton Avery, Peter Doig, Andrew Wyeth, David Hockney and Sidney Nolan. Gallery East Asian tradition China Landscape painting has been called "China's greatest contribution to the art of the world", and owes its special character to the Taoist (Daoist) tradition in Chinese culture. William Watson notes that "It has been said that the role of landscape art in Chinese painting corresponds to that of the nude in the west, as a theme unvarying in itself, but made the vehicle of infinite nuances of vision and feeling". There are increasingly sophisticated landscape backgrounds to figure subjects showing hunting, farming or animals from the Han dynasty onwards, with surviving examples mostly in stone or clay reliefs from tombs, which are presumed to follow the prevailing styles in painting, no doubt without