Anthony Mackie wants to get something off his chest before answering any questions.

“That Meow (Wolf Denver) museum is the craziest (stuff) I’ve ever seen in my life,” said the 46-year-old actor, unprompted, referring to the surreal installation just west of downtown.

That’s saying something, given Mackie’s career as an action hero and low-key heartthrob. As a veteran of the Marvel Cinematic Universe, he’s finally making his film debut as the new Captain America in Marvel’s “Captain America: Brave New World” on Feb. 14, 2025 — following the groundwork laid by his 2021 Disney+ series “The Falcon and the Winter Soldier.”

More recently, Mackie’s been battling monsters in the post-apocalyptic thriller “Elevation,” which was shot mostly in Boulder and Golden and is in theaters now. He plays Will, a father desperate to find medical supplies for his ailing son. That forces him to descend the 8,000-foot-and-higher safety zone of the Rocky Mountains, and into the lower-elevation danger zone where vicious monsters roam free.

That danger zone? Boulder — which is rendered as an empty town just starting to be reclaimed by nature, following the disaster that violently erased most of the human race. The film co-stars Morena Baccarin (in arguably one of her best roles) as disillusioned scientist Nina, and Maddie Hasson as salty young traveler Katie. Together, they navigate abandoned tunnels, an empty hospital and other spooky locales while taking center-frame in gorgeous drone shots of Colorado’s piney expanses.

“I was surprised at the level of chill of everybody in Boulder. Maybe they were all high? But a lot of them weren’t,” Mackie said. “Except for that one old lady in the gym. You know who you are, and you’re mean.”

Mackie likes to do superset workouts, he said, so he would do a heavy press with a medium fly, for example, without taking breaks between machines. Mackie’s elderly nemesis, who stared him down throughout his workouts, copied everything he did.

“So I’m like, ‘Fine, I’m just going to do some rows and pull-ups.’ And she comes around and is like, ‘You can’t even do a pull-up!’ ” he said with a laugh. “And I’d have my headphones in, and she’d be like, ‘Excuse me, no phone in the gym.’ I was about ready to fly my sister in to fight this girl and go Liam Neeson on her.”

He jests, but he took his promo duties for “Elevation” seriously. Mackie and “Elevation” director George Nolfi (“The Adjustment Bureau,” “Spectral”) visited the Denver Film Festival on Nov. 4 to screen and talk about the movie. Mackie even made it up to visit with buddy Deion Sanders in Boulder, hosting a screening for Coach Prime, the University of Colorado Boulder football team, and Super Bowl champ Warren Sapp — as well as a separate Boulder cast-and-crew screening, followed by the Denver Film Fest visit. Phew.

“I did go to a lot of University of Colorado football games while we were shooting,” Mackie said. “But (Sanders) had told me Boulder was like the Atlanta of the West Coast. I must have missed it by two months! When I was in Boulder I was the only Black dude there. Kiss my (butt), Deion Sanders.”

Mackie’s first few weeks of filming in Colorado in late 2022 were challenging in a different way. As a New Orleans resident, he went from sea level to elevations of up to 11,000 feet, he said. He and his stunt man would jog together every day, and go hiking every third day in the Flatirons.

“It was painful coming back from Colorado to New Orleans because the air is so heavy and I was so opened up,” he said. “I felt like I was taking in so much water with my breathing.”

He loved Colorado, but doesn’t miss Boulder much, dubbing it an isolating place that’s “myopic” in its approach to communal dwelling and living in general. The isolation helped with his performance in “Elevation,” he said, since his character Will goes through the same feelings.

“I’ll tell you what I learned in Colorado,” Mackie said. “I thought there would be good fishing, beautiful countryside, all of that. And I was right. The fly fishing was amazing, I got a lot of brookies (trout), but I didn’t go hunting, which I was mad about. Next time I’m coming back hard.”