How many?

Kilometres

The kilometre, or kilometer in American English, is a unit of length in the metric system, equal to one thousand metres. Many people know a marathon race is 26.2 miles long but did you know that a marathon is 42.195 in kilometres?

Fathoms

A fathom is a unit of length in the imperial and the U.S. customary systems equal to 72 inches (1,828.8000 mm), used especially for measuring the depth of water. The Atlantic Ocean at its deepest point is believed to be 4,580 fathoms deep.