Alex Simmons knew that her boyfriend was going to propose the day it happened.

What she didn't know is that she'd first spend the day logging her progress by GPS until she climbed more stairs than she could count and arrived at a bench where the proposal, written on a piece of paper, was stuck inside a container that looked like a rusty bolt.

"Basically, I had to go up 50 bajillion flights of stairs to get this stupid ring," Simmons joked.

Simmons and her now-fiance, Ansell Toskas, were geocaching — a hobby growing in popularity around the world. Minnesota, where many parks host geocaching events and rent out equipment, is no exception.

In traditional geocaching, players set out using GPS technology, such as a special handheld device made for geocaching or a mobile phone, and an online database or mobile app to find a hidden package, or "cache." Caches are usually a waterproof box with a trinket and a log inside, where visitors sign their names

The hobby, which started in 2000 with 75 known caches worldwide, now boasts more than 2.5 million caches, according to geocaching.com, one of the oldest and well-known geocaching sites today. The site has more than 10 million registered users.

Toskas, who has gone geocaching a handful of times, has noticed how large the community has become, not only in Minnesota, but in other states where he has searched for caches.

"The other times that I've tried it, I've run into other people geocaching," Toskas said. "It's kind of cool, it feels like you are in this little club."

Caches are hidden across Minnesota, in rural and urban areas, said Josh Sweet, program and facility specialist for Three Rivers Park District. He's been an avid geocacher since 2009.

"I always am amazed at how many are out there," Sweet said. "If you go to the geocaching website and you search a radius of your home, or wherever you might be, [it's] almost guaranteed there's at least five within a square mile of where you're standing."

Sweet oversees the geocaching programs Three Rivers offers at parks around the metro, where visitors can check out handheld GPS equipment for free.

Seeking s'mores

In Scott County, Three Rivers offers GPS equipment for checkout at Cleary Lake Regional Park. The park district also hosts Geocaching for S'mores events throughout the year at Cedar Lake Farm Regional Park and Cleary Lake Regional Park to teach people the basics.

"It's been very popular with Scouts, with families and those that are kind of beginners and kind of trying to get a taste for what geocaching is like," Sweet said.

Geocaching for S'mores is exactly what it sounds like: Participants find hidden caches around the parks that hold cards listing an ingredient for the campfire treat. At the end, everyone submits the cards in exchange for ingredients and gets to enjoy s'mores as a group.

The event is good for people who are new to geocaching, Sweet said, because the caches are somewhat easy to find and participants go searching in pairs or groups.

Later this year, Three Rivers also plans to start a new geocaching event called Geocaching When the Moon is Full, where those looking for a challenge can try to find caches around the park after the sun goes down.

"If you've done Geocaching for S'mores already and you're ready for a new challenge, this is kind of that 200 level course," Sweet said.

One of the biggest benefits of geocaching is encouraging people to merge existing technology interests with being outside and getting active, Sweet said. Young people, especially, tend to catch on to geocaching technology quickly.

"More people are realizing that this is a great way to get people into the outdoors who still enjoy being attached to their technology," he said. "And this isn't just a hobby. This is a sport for some people … This is what they do to exercise."

Getting outdoors is exactly what motivated Simmons to try out geocaching when Toskas initially invited her for her first cache-finding adventure.

"And also, there's this very attractive man who likes me and I wanted to impress him … with how many stairs I can walk up," Simmons said. "So there's that too."

Simmons and Toskas plan to marry in October.

Janice Bitters is a Twin Cities-based freelance writer.