I believe you're thinking of the Greenwich Observatory in London, England.
The place name associated with the 0 degree meridian is Greenwich, London, United Kingdom. This is where the Prime Meridian is located and is considered the starting point for measuring longitude. The Royal Observatory in Greenwich marks the spot where the Prime Meridian passes through.
Greenwhich
greenwich
It is 0 degrees.
0 degree longitude is is called the Prime Meridian.
Prime meridian
the prime meridian(:
dude, your funny 0*
The Prime Meridian is at zero degrees longitude and every possible latitude.
The prime meridian is a line at 0 degrees longitude.
The Prime Meridian
It was chosen as the base 0 degree meridian for longitude.