Time to synchronize our clocks now to the Geo Quiz: we're searching for a district of London. It's home to the Royal Observatory which looks out over the River Thames. The observatory marks the location of the prime meridian. That's 0 degrees longitude. It serves as the starting point for all time zones spanning the globe.
If longitude and meridians and UTC make your head spin then just try to come up with the name of this London district….
The answer is of course. Greenwich — birthplace of Greenwich Mean Time.
Anchor Marco Werman talks with author Mark Ovenden who wrote and edited the book Transit Maps of the World, now he's got another volume out, called Railway Maps of the World. It includes one story which tells where the idea of Greenwich Mean Time came from and the whole concept of mean time and time zones.