Four historic Chicago storefronts will survive a massive retail and residential gut job thanks to a restoration process little-used in the United States. The only way to save the shops' 100-foot-by-200-foot masonry and terra cotta façades was to sink 18 concrete caissons 80 feet into the ground and build a massive steel support system, says Shawn Hunt, principal, Mesa Development, part of a team that is building the downtown Chicago project. The process isn't cheap. At about $2.5 million, the cost is twice as much as traditional construction, says Hunt.

The façades, from buildings constructed just after the 1871 Chicago fire, will front 100,000 square feet of retail space in The Heritage Shops, part of a 59-story condominium complex. Individual stores' footprints are often too small for modern retail development.

By preserving four in a row, retailers get much-needed uninterrupted space. And the façades' Main Street feel gives customers the nostalgia they're looking for while maintaining a landmark, says Jim Klutznick of Klutznick-Fisher Development, which is overseeing development of the shops.