Have you visited New York City? What about this bustling city stands out to you? What about Washington, D.C.? What’s the No. 1 thing that comes to mind when you think about your visit to the nation’s capitol? How about San Francisco? What is your fondest memory of this West Coast hub?

I’m going to bet that some of your most memorable and meaningful experiences in these iconic major metropolitan areas revolve around the outdoors. Think Central Park in New York City, Golden Gate Park in San Francisco, or the cherry blossoms blooming in Washington, D.C.

Studies consistently show people tend to live healthier and happier lives in areas where they have access to nature, particularly urban areas that dedicate land to green spaces.

And the more space devoted to nature a city has, the more memorable that place becomes for residents and visitors.

Washington, D.C., devotes one-fifth of its land to parks. Green spaces account for almost 18 percent of San Francisco. In fact, the San Francisco Recreation and Parks Department spends $140 per each of its more than 800,000 residents on the park system. The money certainly goes to good use with nearly all of the residents being within a 10-minute walk to a park. And New York City boasts more than 38,000 square acres of park, which accounts for almost 20 percent of the city area.

I’ve been to all three of these major metropolitan cities more than once. And I can tell you I have very clear memories of strolling through Central Park, watching the fog hang low over the Golden Gate Bridge and enjoying the gorgeous cherry blossoms blooming around the Tidal Basin and welcoming spring in D.C.

Recent high-profile projects like Millennium Park have captured public attention for the landscape architects designing them. Since outdoor spaces are some of the least expensive to create, paying some of the highest returns on investment, and more people are returning to urban areas, continuing to invest in these green spaces makes sense.

“Landscape architects understand the natural environment, the built environment and the interface between them,” explains Kirt Martin, vice president of design and marketing at Landscape Forms. “And they are ideally prepared to take leadership in shaping outdoor spaces and framing public awareness about them.”

But buildings and their interiors continue to receive much more attention and financial support than their exteriors. “We have not made a strong business case for designed outdoor spaces,” Martin says. “I believe the design and innovation in public and privately owned outdoor spaces is lagging• — and the first step to address that challenge is to better leverage the skills and talents of landscape architects, the professionals best prepared to design them.”

Editor’s note: This article was originally published in September 2015.