[West of the Greenwich Line]
Greenwich 00° 00′ W
Montreal 73° 34′ W
Ottawa 75° 43′ W
Chicago 87° 45′ W
New York 73° 50′ W
Madrid 3° 43′ W
Washington 77° 00′ W
Lisbon 9° 08′ W
Los Angeles 118° 15′ W
Casablanca 7° 35′ W
Dallas 96° 48′ W
Bermuda 64° 30′ W
Bahamas 78° 00′ W
Havana 82° 23′ W
Honolulu 157° 50′ W
Mexico City 99° 10′ W
Kingston 76° 48′ W
Barbados 59° 30′ W
Caracas 66° 56′ W
Panama 79° 32′ W
Accra 00° 06′ W
Bogota 74° 05′ W
Quito 78° 35′ W

[East of the Greenwich Line]
Greenwich 00° 00′ E
Rome 12° 30′ E
Istanbul 28° 57′ E
Beijing 116° 25′ E
Athens 23° 44′ E
Seoul 127° 00′ E
Tokyo 139° 45′ E
Tehran 51° 26′ E
Jerusalem 35° 13′ E
Cairo 31° 15′ E
Riyadh 46° 46′ E
Hong Kong 114° 15′ E
Hanoi 105° 54′ E
Rangoon 96° 10′ E
Bangkok 100° 30′ E
Saigon 106° 43′ E
Addis Ababa 38° 02′ E
Bombay 72° 51′ E
Colombo 79° 52′ E
Lagos 3° 28′ E
Kuala Lumpur 101° 26′ E
Singapore 103° 50′ E
Nairobi 36° 50′ E
Jakarta 106° 49′ E

The historic line passing through the Royal Greenwich Observatory divides the Earth into East and West.
The line was determined in 1884 at the International Meridian Conference.

The sign shows major cities in the world and the longitude that passes through it.

In the next photo taken that day, you can see the line starting from the Royal Observatory. And a group of visitors who are mostly "on the eastern side" Click for a larger image

In the next sign taken from inside the building, you can see the sign indicating the longitude, located in the place where the Greenwich Line telescope is located Click for sign's details

In the following photos taken on the same day, additional parts of the line appear, with additional cities and their longitude indicated.
Click for a larger image Click for a larger image Click for a larger image