SAN FRANCISCO -- A piece of San Francisco's past was unearthed earlier this month when wreckage from the old City Hall -- destroyed in the 1906 earthquake that devastated the city -- were discovered at a construction site.

Workers digging underneath a Hyde Street sidewalk uncovered bricks, concrete and steel reinforcing bars earlier this month, according to the San Francisco Chronicle.

Federal archaeologists were brought in -- the site at 50 United Nations Plaza sits adjacent to a former federal building -- and after consulting old maps and reports, determined the rubble was the old City Hall.

"We were surprised to see it," Rebecca Karberg, a historic preservation specialist for the General Services Administration, told the newspaper. "You really never know what's under the surface."

The ornate, 300-foot-tall domed building opened in 1897 after 25 years of construction, the Chronicle reported.

The largest municipal building west of Chicago was supposed to be earthquake-proof but was damaged by a minor temblor a year after it opened.

When the 1906 earthquake shook the city, City Hall collapsed in seconds.

The skeletal wreckage became a symbol of the city's infamous disaster, the newspaper said, and photographs were sold as postcards.

The rest of the building was demolished in 1909.

Architects and historians told the Chronicle they intend to document the newly discovered ruins before the landscaping project continues. But then?

"We will bury it all again," Karberg said.