Mark Wahlberg Goes Scuba Diving in Awesome New Aquarium

Mark Wahlberg's gone into the abyss ... of landlocked Missouri, and he's loving it.

Marky Mark hit up the grand opening of the Wonders of Wildlife National Museum & Aquarium in Springfield, MO ... the handiwork of Bass Pro Shops CEO Johnny Morris.

Mark was the special guest and later dove into the 2-story, 1.5 million gallon aquarium in front of conservation leaders from around the globe. Construction of the museum and aquarium reportedly took a whopping 9 years.

The museum features 35,000 live fish and mammals. That does not include Mark.