The event featured several different activities, ranging from building a bird house to planting trees. It was held at the M.W. Boudreaux Memorial Visitors Center and the Frank Russell Reaction Area.
Earth Day has been celebrated at Mark Twain Lake for more than 20 years. The groups that work with the Park on the event include the St. Louis Area Geocachers Association, the Lakes of Missouri Volunteer Program, and several others.
Toni Lake and her family enjoyed all of activities at the event, ranging from geocaching to building bird houses.
"They enjoyed it a lot because they got to play with gadgets like GPS and they enjoyed getting bird houses made because that was kind of hands-on and they got to participate in that," Lake said of her sons.
She found Earth Day to be the perfect opportunity to teach her sons to appreciate the outdoors.
"You have to teach them, they're not going to learn without a good example. It's a lot easier just to sit inside and watch TV and play video games," said Lake.
Ranger Ben Sapp that the goal of the event was to get people back in touch with nature.
"Unfortunately, we're losing touch with some of the basic things that a lot of us did when we were growing up. We're trying to find ways to infuse that," Sapp said.
Gene Havens, a geocacher who volunteered to run a presentation about his hobby at the event, said there was another lesson to be learned from the event.
"Everyone should be familiar with their surroundings and need to help preserve them, because our kids will need an earth and their kids will need an earth," Havens said.
For Lake and her family, enjoying nature and taking care of it go hand in hand.
"We're teaching them about having fun outside, which is a good reason to protect it."
More than 50 people attended the event, which began at 9 a.m. and lasted into the early afternoon.