Geocaching is a treasure hunt using high-tech tools — or as one geocacher noted, using billion dollar satellites to find Tupperware.

After Bill Geary of St. Peter retired in 2005, his wife bought him a GPS. “That started me,” he said.

An enthusiastic participant of geocaching, Geary (aka Ramsey63) has found 1273 caches in two years. “I’ve done all the rest areas between here and New Jersey,” he said.

Ramsey63 has measured the flow of a creek, deciphered bar codes, boated to an island in Lake Jefferson and translated Swahili — all to find the longitude and latitude coordinates to plug into a GPS (global positioning system) to find hidden caches.

Finding the cache is the reward.

Most beginners try to find regular caches without solving puzzles using GPS coordinates found on the Internet. These caches contain a logbook, and usually a few trinkets for trade, in a weatherproof container.

These treasures can be just about anything, but usually are coins, pins, cards, key chains or small toys. Once the stash has been located, the finder signs the logbook. If a treasure is taken out, it is replaced with something else.

“I love it,” said the geocacher known as International Family, who has found about 50 caches.

But for Jo E. Anderson, a retired physician in Le Sueur, the fun is teaching geocaching in a Le Sueur Youth Opportunities program.

Anderson takes his geo-kids on field trips to find caches. “Kids are really into this,” Anderson said. “They have the ability to think outside the box.”

Geocachers also hide caches for others to find. This year Anderson’s students planted a travel bug in a cache. A note attached to a toy zebra states, “My name is Zebbie the zoo zebra and my mission is to travel to zoos.”

“The program allows us to be contacted by e-mail when the zebra goes to another place,” Anderson said. Since July Zebbie has traveled to caches in St. Peter, near the Chicago zoo, Missouri and then close to the St. Louis zoo with the help of cachers who find the zebra in one cache and take it to another.

The hunt for caches usually starts at the game’s main Web site, geocaching.com by entering a ZIP code or city. A list of caches in the area pops up on the screen. For example, there are 86 active caches within 20 miles of Mankato.

Although the GPS determines the general location, identifying the specific location becomes the challenge. A GPS can have a margin or error up to 20 feet, Geary said. “It’s taken me to a lot of interesting places.”

Discovering and learning is part of the sport. The search for one cache led Geary to the Arlington Cemetery tombstone of one of the men who caught John Wilkes Booth.