Although it is a modern building, Wyatt says it seems at home on the site, incorporating the traditional red brick, limestone and massing historically used on the campus.

The site grade varies by 17 ft from its north to south sides. On the south side, all three levels are open to a park area, but on the north, people will enter into the second floor.

The 67-ft-tall Freedom Hall entrance features a square glass box, which allows natural light into the center of the building, and a large video board on all four walls. A 5,400-sq-ft, 360-degree LED media wall will prepare visitors for the exhibit.

Manhattan completed the exterior brick, limestone and high-efficiency glass exterior this spring. Some of the limestone comes from Midland, Texas, where Laura and George Bush formerly lived.

The project team sourced local materials for the project within 500 miles, including the stone, flooring and finish woods from Texas and brick from Mississippi. They avoided materials with volatile organic compounds.

The building sits on 511 drilled straight-shaft piers, reaching to depths of 30 ft into the limestone below, with a mud slab and crawl space below the structure of steel and poured-in-place concrete.

Structural engineer Walter P Moore specified a minimum 15% fly ash content in the foundation concrete and a 56-day concrete strength, instead of the typical 28-day strength, to reduce cement content. The project used dry-kiln Portland cement. To span the auditorium roof, one of three green roofs, the engineers used a two-way, post-tensioned concrete system.

Steel was used in the tower, the Oval Office replica and the exhibit space to create clear spans. Tube-steel frames support much of the exhibit space. Floating ceilings are suspended from a Unistrut frame. Small-diameter aircraft cable supports a 5,000-lb piece of memorial steel from the World Trade Center that will be on display, says Peter Range, an associate with Walter P Moore.

Walter P Moore designed the structure to meet blast and progressive-collapse requirements set by the National Archives and Records Administration, an independent agency, with additional support for the archival areas.

"The program requirements required us to have a multitude of transfer girders, step slabs and thickened slabs," he says. "We also had to have some blast hardening for certain aspects of the structure."