In 40 cities around the United States today, Sept. 21, architecture firms, arts collectives, landscape design firms, activists, and other groups of citizenry are taking over metered parking spaces, laying sod, and creating a variety of temporary parks, playgrounds, and social gathering places for the enjoyment and consideration of passersby. It's called National Park(ing) Day, and its goal is to promote the need for more city parks.

The first Park(ing) Day—a single temporary park in downtown San Francisco—was held by local arts collective Rebar in 2005 as an "intervention into the public realm" that sought to alter the way public space in cities is perceived. In 2006, the Trust for Public Land (TPL, www.tpl.org), which conserves land for people to enjoy as parks, community gardens, historic sites, and other natural places, took up the concept as a logical extension of its own mission. According to the TPL, as many as two in three city residents in America do not have access to nearby parks, playgrounds, or open space.

The national nonprofit organized Park(ing) Day 2006 in conjunction with Rebar and spread the event throughout San Francisco and beyond, to different cities around the nation and the globe. In all, there were 47 temporary parks created worldwide. This year, Rebar and the TPL are joined as sponsors of National Park(ing) Day by the San Francisco nonprofit Public Architecture.

"The range of cities participating this year is phenomenal, really wonderful—broad participation across the spectrum of the kinds of American cities that are experiencing all different kinds of park needs, whether it's small parks closer to home or big destination parks," says Matthew Shaffer, media representative for the TPL.

Forty cities are participating in National Park(ing) Day today, with 100 parks being set up to draw attention to the need for more parks in American cities and to temporarily expand the green spaces available to those who live and work in cities. The parks range from simple grass-and-bench sitting areas and musical venues to dog parks and art/sculpture exhibits.

The Kentucky Chapter of the American Society of Landscape Architects (KYASLA) has taken a more direct educational approach for Park(ing) Day with its two Louisville parks. The KYASLA team has incorporated sod, trees, flowers, and benches but has also set up displays that explain the urban heat-island effect. Thermometers—one set on the grass and one set on the adjacent paved areas—connected to a digital display demonstrate the difference in ambient temperature that landscaping can make.

"We're hoping that this will get people to think about the benefit you get from a park—not just that they're a nice place to go and have lunch, but that they have real, tangible benefits," says KYASLA member John Pacyga of Gresham, Smith and Partners.

Several teams from the Los Angeles Chapter of the AIA are participating, and the chapter has tied its members' Park(ing) Day activities into its own promotion and discussion of how Los Angeles can create and sustain more parks and public spaces. The effort will culminate in its first Public Space LA Summit on Oct. 26, 2007. The one-day summit is part of AIA-LA's annual expo and design conference.

"The drive really is for the city of Los Angeles to create opportunities for parks and open space and public plazas within walking distance to everyone," says Will Wright, AIA-LA's director of public and government affairs.

According to the TPL, neighborhood parks reduce crime, revitalize neighborhood economies, and help protect the local environment. Among the social, health, and environmental benefits that parks support, they also beautify and remind people of our connection to nature, even in the center of a bustling metropolis. Most Park(ing) Day parks are no larger than the average Hummer SUV, but the impact of these tiny islands of greenery and serenity in a sea of concrete and stone can be big.