
Geocaching is an outdoor sport activity based on GPS (Global Positioning System). Players use a receiver or mobile device and other navigational techniques to hide or look for containers, called "geocaches" or "caches".

One of the main ideas of geocaching is putting caches in places that are interesting, but not often visited by tourists. In the listing of the cache, information about the places is given.
After 25 years of activity there are over 3,500,000 active geocaches. There are over 5 million geocachers worldwide.
Geocaching was invented shortly after the removal of artificial error from GPS on May 2, 2000. Accuracy of the GPS before this date was about 100m, after this date is less than 3m. Improved accuracy allowed geocachers to specify where caches are located.
The first cache was placed on May 3, 2000, by Dave Ulmer in Beavercreek. It was found by Mike Teague of Vancouver on May 6, 2000. The original name of the game is GPS Stash Hunt, but it was changed on May 30, 2000 after the discussion of several players to Geocaching.
The cache is usually in a waterproof plastic container with a logbook where geocachers write their registered nickname and date they find it. Larger containers usually contain items for trading like plastic toys, hockey cards or special trackable items called Travel Bugs or Geocoins. Trackable items are logged on the website and moved from cache to cache.
The coordinates of a hidden cache with the rating of the difficulty and terrain and information about size are placed by owner at the official website Geocaching.com. After checking by a reviewer, they are published and available for other gteocachers.