The meter is the base SI unit of length. It was first defined in 1793 as one ten-millionth of the distance from the equator to the North Pole through Paris. Today it is defined as the distance light travels in vacuum in 1/299,792,458 of a second โ a definition tied directly to the universal speed of light. The meter is the foundation of the metric system used by 95% of the world.
Real-world: A standard door is about 2 metres tall. An Olympic swimming pool is exactly 50 metres long. The Eiffel Tower is 330 metres tall.
Read full meter reference โThe nautical mile equals 1852 meters exactly โ defined as one minute of arc along a meridian. It is the standard distance unit for marine and air navigation worldwide. Ship and aircraft speeds are given in knots, where 1 knot = 1 nautical mile per hour.
Real-world: Territorial waters extend 12 nautical miles from the coastline. London Heathrow to New York JFK is about 3000 nmi.
Read full nautical mile reference โ