The Paul Bunyan State Trail offers views of sparkling lakes, visits to quaint towns and now geocaching, an open-air, free, GPS-enhanced treasure hunt.

In geocaching, technology meets the great outdoors. Participants  look for hidden containers, called geocaches, using a smartphone or GPS. The cache -- which range in size from a pill bottle to a mailbox -- will typically hold a log book with names of those who have previously found it. Some also contain trinkets or medallions that cachers can use to trade or move to the next cache. There are more than 100 geocaches along the rails-to-trails paved pathway, which at 112 miles between Brainerd and Bemidji, is the longest  trail in the state. Download the GeoTour here.

You'll find caches such as "Paul's Sawmill," described in part like this: "At the location of this cache, one can see the remnants of our early logging heritage. Enjoy the cache and watch for fishermen." And "Northern Troll," which comes with this warning, "This cache introduces you to an area of Bemidji that is oftentimes overlooked. Enjoy the walk and the scenery but be on the look out for trolls."