Kilometre

The kilometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: km; /ˈkɪləmiːtə/ or /kɪˈlɒmɪtə/) or kilometer (American spelling) is a unit of length in the metric system, equal to one thousand metres (kilo- being the SI prefix for 7003100000000000000♠1000). It is now the measurement unit used officially for expressing distances between geographical places on land in most of the world; notable exceptions are the United States and the road network of the United Kingdom where the statute mile is the official unit used.

k (pronounced /keɪ/) is occasionally used in some English-speaking countries as an alternative for the word kilometre in colloquial writing and speech. A slang term for the kilometre in the US military is klick.

Pronunciation

There are two common pronunciations for the word.

The former follows a pattern in English whereby metric units are pronounced with the stress on the first syllable, and the pronunciation of the actual base unit does not change irrespective of the prefix. It is generally preferred by the British Broadcasting Corporation (BBC) and the Australian Broadcasting Corporation (ABC).

1 kilometre

To help compare different orders of magnitude this page lists lengths between 1 kilometre and 10 kilometres (10³ and 10⁴metres).

Conversions

1 kilometre (unit symbol km) is equal to:

Human-defined scales and structures

Kilometre zero

In many countries, Kilometre Zero (also written km 0) or similar terms in other languages (also known as Zero mile marker, control stations or control points) is a particular location (often in the nation's capital city), from which distances are traditionally measured. They were markers where drivers could set their odometers to follow directions in early guide books.

A similar notion also exists for individual roads (that is, all locations on the road have a number, depending on their distance from that location), and for individual cities (often the city's central post office is used for this).

The most famous such marker of which any part survives from ancient times is the Milliarium Aureum ("Golden Milestone") of the Roman Empire, believed to be the literal origin for the maxim that "all roads lead to Rome".

Countries

Argentina

Argentina marks Kilometre Zero with a monolith in Plaza Congreso in Buenos Aires. The work of the brothers Máximo and José Fioravanti, the structure was placed on the north side of Plaza Lorea on October 2, 1935; it was moved to its present location on May 18, 1944. An image of Our Lady of Luján (honored on the monolith as "the patron saint of the national road network") appears on the monolith's north face, a relief map of Argentina is on the south face, plaques in honor of José de San Martín are west, and on its eastern side, the date of the decree and the name of the relevant authorities.