SEATTLE - The City of Seattle and a group of volunteers are trying to get more people to visit a unique landmark that many drivers just ignore.

“Did you not realize there's like a concrete inverted Mayan pyramid in the center of Seattle?” said Colin MacDonald, who practices parkour, a kind of urban gymnastics, at Jim Ellis Freeway Park.

That's one way to describe the swath of green space above I-5 near the convention center, which turns 40 this weekend.

“This is the largest open public space in the city. It is 5.2 acres,” said Bob Anderson, board president of the Jim Ellis Freeway Park Association. “So we want to make this space even more available and more visible to the public, and more interesting.”

The park, at times in its history, became an overgrown, rough patch of concrete, which you might have wanted to avoid. But as visitors gathered to celebrate the park's birthday, the city and the Freeway Park Association were also marking a comeback.

“We've totally replanted the park, and there's light and life in the park,” Anderson said.

They've trimmed the vegetation, improved security, and this summer they're adding more live music, gardening classes, yoga, and dance lessons.

“We're giving people reasons to come here, not just to walk around it,” Anderson said.

“I personally never felt unsafe in this park, but I know people who feel that way, and that makes me sad because I think it's a beautiful space,” MacDonald said.