qualities of his buildings, and their relationship with the landscape. The five concrete shells of the structure resemble seashells by the beach. Begun in 1957, the project encountered considerable technical difficulties making the shells and getting the acoustics right. Utzon resigned in 1966, and the opera house was not finished until 1973, ten years after its scheduled completion. In India, modernist architecture was promoted by the postcolonial state under Prime Minister Jawaharlal Nehru, most notably by inviting Le Corbusier to design the city of Chandigarh. Important Indian modernist architects include BV Doshi, Charles Correa, Raj Rewal, Achyut Kanvinde, and Habib Rahman. Much discussion around modernist architecture took place in the journal MARG. In Sri Lanka, Geoffrey Bawa pioneered tropical modernism. Minnette De Silva was an important Sri Lankan modernist architect. Post independence architecture in Pakistan is a blend of Islamic and modern styles of architecture with influences from Mughal, indo-Islamic and international architectural designs. The 1960s and 1970s was a period of architectural Significance. Jinnah's Mausoleum, Minar e Pakistan, Bab e Khyber, Islamic summit minar and the Faisal mosque date from this time. Africa Some notable modernist architects in Morocco were Elie Azagury and Jean-François Zevaco. Asmara, capitol of Eritrea, is well known for its modernist architecture dating from the period of Italian colonization. Preservation Several works or collections of modern architecture have been designated by UNESCO as World Heritage Sites. In addition to the early experiments associated with Art Nouveau, these include a number of the structures mentioned above in this article: the Rietveld Schröder House in Utrecht, the Bauhaus structures in Weimar, Dessau, and Bernau, the Berlin Modernism Housing Estates, the White City of Tel Aviv, the city of Asmara, the city of Brasilia, the Ciudad Universitaria of UNAM in Mexico City and the University City of Caracas in Venezuela, the Sydney Opera House, and the Centennial Hall in Wrocław, along with select works from Le Corbursier and Frank Lloyd Wright. Private organizations such as Docomomo International, the World Monuments Fund, and the Recent Past Preservation Network are working to safeguard and document imperiled Modern architecture. In 2006, the World Monuments Fund launched Modernism at Risk, an advocacy and conservation program. The organization MAMMA. is working to document and preserve modernist architecture in Morocco. See also Modernisme Modern furniture Modern art Organic architecture Critical regionalism Complementary architecture List of post-war Category A listed buildings in Scotland New Urbanism