The UTM system divides the Earth between 80°S and 84°N latitude into 60 zones, each 6° of longitude in width. The zones are numbered from 1 to 60 proceeding east from the anitmeridian (180°).
This rotating Transverse Mercator projection shows the 60 UTM zones around the Earth. The projection has constant scale along the changing central meridian, and regions near it are mapped with low distortion. Just like on the regular Mercator projection, areas further away from the central meridian are increasingly distorted.
UTM is often used to show regions or countries with a greater north-south extent, like mainland Norway, which is usually depicted in UTM 33.