industry is located in and around the city thus earning it the nickname "Detroit of India". Known as the "Gateway of South India", Chennai is the third-most visited city in India by international tourists according to Euromonitor. The city is also called the Cultural Capital of South India. The city was home to the Madras Stock Exchange, India's fourth stock exchange, one of four permanently recognised by SEBI, and India's third-largest by trading volume, ranked behind the Bombay Stock Exchange and the National Stock Exchange of India. Industrialisation in the city dates back to the 16th century, when textile mills manufactured goods which were exported to British during its war with France. According to Forbes magazine, Chennai is one of the fastest-growing cities in the world and is ranked among the "Forbes-Top 10 Fastest Growing Cities in the World". It is ranked 4th in hosting the maximum number of Fortune 500 companies of India, next only to Mumbai, Delhi and Kolkata. It also is home to 24 Indian companies having a net worth of more than US$1 billion. , the city has about 34,260 identified companies in its 15 zones, of which 5,196 companies have a paid-up the capital of over 50 lakh. Chennai has a diversified economic base anchored by the automobile, software services, hardware manufacturing, health care and financial services industries. According to the Confederation of Indian Industry, Chennai is estimated to grow to a US$100 billion economy, 2.5 times its present size, by 2025. , with 1 lakh crore investment in the pipeline over 5 years, the city is poised for major industrial investment. Chennai is classified as a global city by GaWC, with a ranking of Beta based on the extent of global reach and financial influence. It is estimated that about 400 financial industry businesses are headquartered in the city, half of which are located in the areas of Mylapore, R. A. Puram, Nungambakkam and T. Nagar. The city is base to around 40 percent of India's automobile industry and 45 percent of auto components industry. A large number of automotive companies including Royal enfield, Hyundai, Renault, Robert Bosch, Nissan Motors, Ashok Leyland, Yamaha Motor, Daimler AG, Caterpillar Inc., Komatsu Limited, BharatBenz, Ford, BMW, Citroën and Mitsubishi have manufacturing plants in Chennai. The Heavy Vehicles Factory at Avadi produces military vehicles, including India's main battle tank: Arjun MBT. The Integral Coach Factory manufactures railway coaches