tradition of political graffiti depicting everything from outrageous slander to witty banter and limericks, caricatures and propaganda. Kolkata has many buildings adorned with Indo-Islamic and Indo-Saracenic architectural motifs. Several well-maintained major buildings from the colonial period have been declared "heritage structures"; others are in various stages of decay. Established in 1814 as the nation's oldest museum, the Indian Museum houses large collections that showcase Indian natural history and Indian art. Marble Palace is a classic example of a European mansion that was built in the city. The Victoria Memorial, a place of interest in Kolkata, has a museum documenting the city's history. The National Library of India is the leading public library in the country while Science City is the largest science centre in the Indian subcontinent. The popularity of commercial theatres in the city has declined since the 1980s. Group theatres of Kolkata, a cultural movement that started in the 1940s contrasting with the then-popular commercial theatres, are theatres that are not professional or commercial, and are centres of various experiments in theme, content, and production; group theatres use the proscenium stage to highlight socially relevant messages. Chitpur locality of the city houses multiple production companies of jatra, a tradition of folk drama popular in rural Bengal. Kolkata is the home of the Bengali cinema industry, dubbed "Tollywood" for Tollygunj, where most of the state's film studios are located. Its long tradition of art films includes globally acclaimed film directors such as Academy Award-winning director Satyajit Ray, Ritwik Ghatak, Mrinal Sen, Tapan Sinha and contemporary directors such as Aparna Sen, Buddhadeb Dasgupta, Goutam Ghose and Rituparno Ghosh. During the 19th and 20th centuries, Bengali literature was modernised through the works of authors such as Ishwar Chandra Vidyasagar, Bankim Chandra Chattopadhyay, Michael Madhusudan Dutt, Rabindranath Tagore, Kazi Nazrul Islam and Sarat Chandra Chattopadhyay. Coupled with social reforms led by Ram Mohan Roy, Swami Vivekananda and others, this constituted a major part of the Bengal Renaissance. The middle and latter parts of the 20th century witnessed the arrival of post-modernism, as well as literary movements such as those espoused by the Kallol movement, hungryalists and the little magazines. Large majority of publishers of the city is concentrated in and around College Street, "... a half-mile of bookshops and bookstalls spilling over onto the pavement", selling new and used books. Kalighat painting originated in 19th century Kolkata as a local style that