Even more crazy when dealing with it as an angular unit as Minute of Arc.
Historically:
1 Minute of Great Arc = 1 Nautical Mile
Great Arc = Earth circumference
1 Minute of Great Arc = Great Arc / (360 * 60)
Fun Fact:
Earth Circumference = 4 times great circle distance Pole to Equator
historically defined as 10000km or 10 Million Meters (They were that serious about being decimal)
That also explains why the earth radius can still approximately be expressed as 10000km/(π/2) = 6366.2km (just 4.8km off the current mean radius defintion of 6371 km)
Historically: 1 Minute of Great Arc = 1 Nautical Mile
Great Arc = Earth circumference
1 Minute of Great Arc = Great Arc / (360 * 60)
Fun Fact:
Earth Circumference = 4 times great circle distance Pole to Equator historically defined as 10000km or 10 Million Meters (They were that serious about being decimal)
That also explains why the earth radius can still approximately be expressed as 10000km/(π/2) = 6366.2km (just 4.8km off the current mean radius defintion of 6371 km)
http://en.wikipedia.org/wiki/Nautical_mile#History