I have been lucky to visit the Greenwich Mean Time line (GMT) at Royal Observatory Greenwich in the United Kingdom all the way from Australia. It is also known as Greenwich Meridian line at zero degrees longitude .
GMT was endorsed globally in 1884 as the Prime Meridian Time line. A line has been drawn across the Royal Observatory courtyard since then to divide East and West. It is no surprise that it is situated in the United Kingdom as they were the leading seafarers at 17-18th centuries.
Current international time zones rotate around this line for the past 1 ½ centuries. GMT has become a popular tourist attraction and visitors stand astride the line to take memento photographs.