geocaching:

Geocaching is an international activity with over 2 million sites worldwide. Participants follow clues to find hidden boxes or containers, known as caches. Caches typically include a logbook and more information on the historical or cultural importance of the site. The Maryville Public Art Committee has planted an unspecified number of geocaches to encourage participants to explore downtown Maryville, see its public art, and learn its history. For more information on how to play, go to geocaching.com.