WASHINGTON - Fifty feet below ground and steps from the U.S. Capitol, construction workers haul bricks and cement, lay marble and tiles and put other finishing touches on a subterranean project almost as large as the building itself.

When completed, the three-level catacomb will be a place to welcome Capitol visitors and make lawmakers safer while doing their business. To some, it also will serve as a tribute to Congress, telling its stories as an institution and as the place where laws are made.