Home to thousands of Kenyan businesses and over 100 major international companies and organizations, including the United Nations Environment Programme (UN Environment) and the United Nations Office at Nairobi (UNON), Nairobi is an established hub for business and culture. The Nairobi Securities Exchange (NSE) is one of the largest in Africa and the second-oldest exchange on the continent. It is Africa's fourth-largest exchange in terms of trading volume, capable of making 10 million trades a day. It also has the Nairobi National Park with a large game reserve. Nairobi is currently under the Nairobi Metropolitan Service.