Bangalore is considered to be one of the fastest-growing global major metropolises. Recent estimates of the metro economy of its urban area has ranked Bangalore as one of the most productive metro areas of India. The city is considered the pivot for high-technology-based heavy manufacturing industry, with numerous large multinational technology corporations setting up their headquarters there. It is home to many top-tier engineering and research institutions. Bangalore is known as the "Silicon Valley of India" because it is the nation's leading software exporter as well as a major semiconductor hub. Several state-owned aerospace and defence organisations are in the city. The presence of numerous notable sporting arenas in Bangalore makes it one of the country's sporting hubs.