Chris Hubing wires shells to the firing rail attached to one tray of tubes on Monday, June 28, six days before the show. Each shell and tube is labeled with its exact order in the show, and then is wired to the proper spot on the firing rail. Each of the 177 rails is connected to the computer system so the shells can be fired at precisely the right time during the show.

A giant light-up clock is the main feature of the ground-based fixtures of this year's display, seen here in its final stages as volunteer Brian Boyer works on it from atop a scissor lift. Designed and crafted by State College Area High School alumna volunteer Katie Salvaggio, the clock utilizes white rope lights masked off to form the clock face, and will illuminate to display 9:32, the time at which the piece will light. The few hundred feet of rope lighting used for this feature was recycled from last year's show.

While groups of volunteers load shells, others are across the field under tents, where they work to unpack, label and sort pieces, including (from left), Rik Harris, Richard Killam, Phil Halleck , Sue Salvaggio and David Babb. Halleck, a retired Penn State engineering professor with a background in explosives research, is in charge of the sorting process.

Empty shipping containers sit in an area away from the sorting tables, as newly arrived shells are unpacked, labeled, sorted and prepared for loading. A total of 15,771 shells will be launched in this year's 45-minute-long show, which is controlled by two computer systems. Approximately 500 volunteers have put in time for this year's event, themed "Star Spangled Spectacular," which is financed entirely by donations. While most volunteer work has already been done, the organizers are glad to have any help in the days following to help clean up after the event.

Onlookers, mostly made up of 4th Fest volunteers, are illuminated by a 5-inch shell as they watch the timing test initiated on Tuesday, June 29. While these volunteers rested and watched the first test examples of their weeks of hard work, other members of the pyrotechnics and safety teams were even closer, but still outside the danger zone nearest to the shells.

A green shell lights up the launch area as it explodes during the timing tests held on Tuesday, June 29, as volunteers (from left) Phil Halleck, Anita Ditz, Gary Mayhew and Matt Lindenberg look on. While other 4th Fest volunteers sat, watched and applauded farther away, the four had their own responsibilities: Halleck kept track of successful shots fired, Ditz announced and verified each shell's size, color and type, Mayhew captured video for choreography timing, and Lindenberg set off each individual shell.