Bogotá – officially named Bogotá, D.C. (D.C. for "Distrito Capital", which means "Capital District"), formerly called Santa Fe de Bogotá – is the capital city of Colombia, as well as the most populous city in the country, with 6,776,009 inhabitants (2005). Bogotá and its metropolitan area, which includes municipalities such as Chía, Cota, Soacha, Cajicá and La Calera, had an estimated population of 8,244,980. In terms of land area, Bogotá is also the largest in Colombia, and its altitude (2,640 metres) makes it the third-highest major city in the world, after La Paz and Quito. With its many universities and libraries, Bogotá has become known as "The Athens of South America"
The TransMilenio rapid transit system, created during Enrique Peñalosa's mayoral term, is a form of bus rapid transit that has been quickly and affordably deployed as an appropriate stopgap measure to compensate for the lack of a metro system. TransMilenio combining articulated buses that operate on dedicated bus roads (busways) and smaller buses (feeders) that operate in residential areas, bringing passengers to the main grid. TransMilenio's main routes are: Caracas Avenue, Northern Highway (Autopista Norte), 80th Street, Americas Avenue, Jiménez Avenue, and 30th Avenue (also referred to as Norte Quito Sur or N.Q.S. for short). Routes for Suba Avenue and Southern Highway (Autopista Sur), the southern leg of the 30th Avenue, were opened in April 2006. The third phase of the system will cover 7th Avenue, 10th Avenue, and 26th Street (or Avenida El Dorado). The system is planned to cover the entire city by 2030. Although the Transmilenio carries commuters to numerous corners of the city, it more expensive than any public transport except taxis, and fares increase with petroleum fuel prices. As of December 2007 the price of a ticket was $1400; however, a single ticket allows unlimited transfers until the passenger leaves the system, and passengers travel on feeder routes for free. Transmilenio does not yet cover some main routes, and buses are overcrowded.
Despite the city's chronic congestion, many of the ideas enacted during the Peñalosa years are regarded worldwide to be cost-effective, efficient and unique solutions. In addition to TransMilenio, the Peñalosa administration and voter-approved referenda helped to establish travel restrictions on private cars during peak hours called Pico y placa, "Car Free Days" on Sundays, a massive system of bicycle paths and segregated lanes called 'ciclorrutas', and the removal of thousands of parking spots in an attempt to make roads more pedestrian-friendly. Ciclorrutas is one of the most extensive dedicated bike path networks of any city in the world, with a total extension of 303 km. It extends from the north of the city, 170th Street, to the south, 27th Street, and from Monserrate on the east to the Bogotá River on the west. The ciclorruta was started by the 1995–1998 Antanas Mockus administration, and considerably extended during the administration of Mayor Peñalosa. Since the construction of the ciclorrutas bicycle use in the city has increased.