You can think of treasure hunt at the global level, which means the artificats can be hidden at any part of this planet 😉
Geocaching an outdoor recreational activity, in which participants use a Global Positioning System (GPS) receiver or mobile device and other navigational techniques to hide and seek containers, called “geocaches” or “caches”, anywhere in the world.
A typical cache is a small waterproof container containing a logbook (with a pen or pencil). The geocacher enters the date they found it and signs it with their established code name. After signing the log, the cache must be placed back exactly where the person found it.
Visit this website for more information related to mobile app which will use GPS and help you to locate the artifact. https://www.geocaching.com/account/welcome