by the 20th century, it was getting more difficult to buy very important paintings; there were other galleries in the united states and germany who were trying to buy the same paintings. so the "national gallery" began to buy works by more modern painters and soon had a collection of 19th and early 20th century paintings. this is not a large part of the "national gallery's" collection, but it does show small works by many very important artists, particularly the impressionists.