often referred to as the 'second city,' chicago is anything but, especially when you consider its latest urban feat, Millennium Park, which opened one year ago. Home to a series of signature art and architecture pieces that include the Frank Gehry-designed Jay Pritzker Pavilion and artist Anish Kapoor's Cloud Gate sculpture, the park is a civic engagement on many levels. This is certainly true of Crown Fountain, from the actual physical experience of the place-two 50-foot-high glass block towers and a 276-foot-long black granite plaza with a shallow water pool-to the recording of 1,000 'faces,' images of Chicago's own citizenry displayed on an LED media screen located behind the glass of each tower's interior elevation.

Although described as a fountain by all, including Spanish artist Jaume Plensa who is responsible for the competition-winning concept, it seems inadequate to label this project, which draws from several disciplines, in such narrow terms. An exemplary study in design and urbanism that creates a place unlike any other, the simplicity of forms masks a complicated set of technical elements and programming sequences that combine water, media, and two types of lighting effects to complete the full experience.

The challenge for the design team, as principal Jim Baney of Chicago-based lighting firm Schuler Shook explains, 'was recognizing that the whole project was the art,' and learning how to translate Plensa's design concept into reality. 'Jaume was the one holding the vision; it was our job to work out the details,' says Baney.

From the outset, in order to maintain the integrity of the tower illumination scheme, Schuler Shook felt it was critically important that no other ambient lighting should illuminate this particular portion of the park. 'We wanted the towers to have a lot of visual impact,' says Baney. To accomplish this, the designers met with the Chicago Parks District. Making their case with documentation that the adjacent light levels from Michigan Avenue provided sufficient peripheral illumination, the project was deemed a special art installation and granted a variance allowing it to disregard the normal footcandle requirements on park walkways, thereby eliminating the need for additional poles or bollards.

A white grazing element occurs at the exterior base of each tower. Two rows of 500W halogen submersible fountain fixtures-60 in total around each tower-are arranged in a grated stainless-steel-covered trough that gathers the cascading water. The front row of luminaires highlights the lower half of the tower, while the back row focuses on the upper section, to provide even illumination. Linear arrays of LEDs, mounted on the tower's interior structure create the colored lighting elements. Placed on seven different levels, each LED row illuminates 8 to 10 feet of glass block.

Even in today's world of sophisticated computer technologies and programming, the lighting team actually used a hand-written diagram, 18 inches wide by 3 feet long, on which Plensa described the programming scripts, what he calls 'life sequences.' There are a total of 10, each comprised of 11 steps that take 35 minutes to play. Each sequence starts with what Plensa refers to as the 'fountain at rest'-everything off except for the running water and the white grazing light. In this state, the towers read as monolithic black structures. A special weir on top of each tower cuts the water off when a face is projected onto the LED screen, preventing the water from disrupting the image visibility.

Black fins in the screens help to shield direct sunlight from hitting the LEDs. The computer that runs the programming is at work 24/7 and selects from a palette of eight colors, creating variations so numerous that the sequences appear random. Photocells in the towers determine when the colored lighting will respond to the computer and when it won't, essentially acting as an electronic sundial. An integral time clock turns the lighting off at midnight.

Part gathering space, part art installation, the project has elicited overwhelming public response. The reaction the design team, including the artist himself, could not have predicted was from children. It has become a special-request destination, especially in the summer months: they have learned to time the cascade of water, running up to the tower face just before the rush of water. Plensa's scheme seeks to marry space, light, and people; urban placemaking has succeeded on all fronts. elizabeth donoff