Óbuda is the oldest district of Budapest. In the 20th century, a residential area formed here with the old city remains in its centre. Zichy-kastély is one of the few historical buildings in Óbuda. The former enfilades are used for three museums today: artist Kassák Lajos, Óbuda history and artist Victor Vasarely. The latter is internationally famous, being the creator and inspirer of op art - a style that makes use of optical illusions. Multidimensional paintings look great in the museum's simple interior. The collection was gifted to the museum by Vasarely, who immigrated to France in 1930. In addition to permanent exhibition, the museum displays the works of artists similar to Vasarely.