Zero degrees latitude and zero degrees longitude is a point in the Atlantic Ocean, south of the African country of Ghana and west of another African country, Gabon.
Or more precisely, about 380 miles (611 kilometers) south of Ghana and 670 miles (1078 km) west of Gabon.
This is where the prime meridian and the Equator intersect.
Zero degrees latitude is the equator, the imaginary line which divides our planet into the northern and southern hemispheres.
Zero degrees longitude is an imaginary vertical line located at Greenwich, England.
Greenwich was established as the site of the prime meridian by an international conference in 1884, and is the site of the British Royal Greenwich Observatory.
John Harrison, a self-educated English clockmaker invented the marine chronometer, a key piece in solving the problem of accurately determining longitude at sea.
This revolutionized and extended the possibility of travelling long distances at sea.