The prime meridian, which passes through the Royal Observatory at Greenwich, England, adopted internationally as the earth's zero of longitude in 1884.
- ‘Here the zero lines of longitude and latitude - the Greenwich meridian and the equator - bisect.’
- ‘It lies 102 ½ metres further east than the official Greenwich meridian and is the line used for all air and sea navigation.’
- ‘By international convention, it passes through the original site of the Royal Observatory in Greenwich, England; for this reason, it is sometimes called the Greenwich meridian.’
- ‘Accurate measurements from space have led to another slight shift of the globe's most important line, and the GPS meridian now lies 102.48 metres east of the old Greenwich meridian.’
- ‘I stop just outside the front door, and am rather pleased to discover that I live exactly 0°1'2 ‘west of the Greenwich meridian.’’
We take a look at several popular, though confusing, punctuation marks.