Middle East and North Africa. The port has undergone reorganisation. Annual tonnage rose to 5.3 million tonnes of goods in 2006. Cartuja 93 is a research and development park, employing 15,000 persons. The Parque Tecnológico y Aeronáutico Aerópolis (Technological and Aeronautical Park) is focused on the aircraft industry. Outside of Seville are nine PS20 solar power towers which use the city's sunny weather to provide most of it with clean and renewable energy. The Sevilla Tower skyscraper was started in March 2008 and was completed in 2015. With a height of and 40 floors, it's the tallest building in Andalusia. Seville has conference facilities, including the Conference and Convention Centre. Research and development The Consejo Superior de Investigaciones Científicas en Sevilla (CSIC) is based in the former Pavilion of Peru in the Maria Luisa Park. In April 2008 the city council of Seville provided a grant to renovate the building to create the Casa de la Ciencia (Science Centre) to encourage popular interest in science. The internationally recognised company Neocodex has its headquarters in Seville; it maintains the first and largest DNA bank in Spain and has made significant contributions to scientific research in genetics. Seville is also considered an important technological and research centre for renewable energy and the aeronautics industry. The output of the research centres in Sevillan universities working in tandem with city government, and the numerous local technology companies, have made Seville a leader among Spanish cities in technological research and development. The Parque Científico Tecnológico Cartuja 93 is a nexus of private and public investment in various fields of research. Principal fields of innovation and research are telecommunications, new technologies, biotechnology (with applications in local agricultural practices), environment and renewable energy. Transport Bus Seville is served by the TUSSAM (Transportes Urbanos de Sevilla) bus network which runs buses throughout the city. The Consorcio de Transportes de Sevilla communicates by bus with all the satellite towns of Seville. Two bus stations serve transportation between surrounding areas and other cities: Plaza de Armas Station, with destinations north and west, and Prado de San Sebastián Station, covering routes to the south and east. Plaza de Armas station has direct bus lines to many Spanish cities as well as Lisbon, Portugal. Metro The Seville metro ("Metro de Sevilla" in Spanish) is a light metro network serving the city of Seville and its metropolitan area. The system is totally independent