Washington State Parks is celebrating its 100th anniversary with a Centennial GeoTour.
The tour allows visitors to uncover 100 geocaches in 100 state parks across Washington.
Geocaching is a family-oriented recreational activity where participants search for hidden containers using a smartphone or GPS.
The centennial geocaches reveal historical facts, hidden vantage points and scenic locations in the state parks.
The first 180 participants to find 50 caches will earn a silver GeoCoin, and the first 30 participants to find 100 caches will earn a gold GeoCoin.
A printable map and passport, along with rules and information, are available at parks.wa.gov/ geocaching.