As its name indicates, the sport field is an area on which sporters do their activities. It can be set differently according to the required configuration for the sport and the degree of proximity and security between the athletes and the spectators.

Boxing : ring
Martial arts : dojo and tatamis
Ball sports : grass, sand, synthetic, hard, clay, parquet floor in a stadium, sports complex or sports center
Swimming : pool inside a swimming pool

We find the first evidences of fields designed for sports back in the Antiquity, during the Antic Olympic Games where the two organizing cities (Elis and Olymp) had a hypodrome, three gymnasiums (for both training and competition, atthletes' quarters and senators' area), a stadium with several tracks, bleachers for spectators, etc. Modern sport just took these great previous inventions for itself !!

The world biggest stadium is the one in Maracana, located in Rio, which can contain up to 200,000 people ! In the US, the Michigan Stadium is the largest, it can hold over 112,000 people.
The world smallest field comes from a team of German researchers that managed to create a soccer field format support of 2 x 1.5 micrometers, namely a millionth of meter !!!