Another name for Greenwich Mean Time, aka Coordinated Universal Time.

It is not called "Zulu Time" because Natal Province in South Africa is in that zone; it isn't.

The United States Navy has assigned a letter to each time zone. The letters don't wrap continuously around the Earth as you might expect. Suffice it to say that "Z" is the letter assigned to GMT. "Zulu" is the phonetic name used for "Z"; thus, "Zulu Time".

The FAA has picked up the same usage, and thus the entire world's civil aviation system uses it.

On March 27, 1964, a magnitude 8 earthquake struck southern Alaska. This earthquake also generated a tsunami which reverberated around the Pacific Ocean. The Navy sent tsunami warnings, giving estimated arrival times.

The trouble was, the Navy issued their estimated times in Zulu Time. Officials in Crescent City, California had no idea what "Zulu Time" was. They had no idea when the tsunami would arrive.

The tsumani arrived in Crescent City, on time, and destroyed the city's docks and hurled a pile of debris at a tank farm, causing a massive fire.

12 people were killed in Crescent City and $7,400,000 of damage (1964 dollars) was done. This was the highest fatality rate and the most damage done outside Alaska.