It is known as Detroit's Cathedral of Finance.

Originally named the Union Guardian Building, this building was created for the Union Trust Co. when it required more space after a merger with the equally huge National Bank of Commerce. It would vacate its 1896 building -- designed by Donaldson & Meier -- for a new structure located across the street on a block bounded by Griswold, Larned and Congress.

The commission for the building went out to Smith, Hinchman & Grylls, which chose one of its noted designers, Wirt C. Rowland, for the job. The result was a 496-foot, 40-story steel-framed building sheathed in 1.8 million orange bricks -- a specially formulated shade dubbed Guardian brick by the architect. The use of brick is unusual in a building of this size from this era. Usually, granite and limestone were used, and the Guardian was the world's tallest masonry structure when it was completed.

This was Rowland's third sizable commission in the city after doing the nearby Buhl and Penobscot buildings. Five buildings were torn down to make way for what would become the Guardian. Demolition on the Huron, Burns, Lewis, Butler and the Standard Savings and Loan Association buildings began on March 1, 1927. The skyscraper was literally founded on bedrock, resting upon 72 caissons sunk through hardpan to bedrock 120 feet below ground. The foundation was completed Oct. 15, 1927. It would open April 2, 1929.

The exterior of the building has a granite base with carvings by Corrado Parducci, with multistory windows surrounded by tile. Rising beyond the base is the orange brick facade, with portions setback to reveal a north and south tower connected to create an I shape. Elegant detail is seen throughout the facade and large amounts visible on the north tower crown.

The interior, however, was as elaborate, if not more so, than the exterior. Upon stepping through the doors, clients of the bank would enter the 150-foot-long main lobby, with a three-story vaulted ceiling above them, that consisted of an Aztec design with multicolor, interlocking hexagons of Rookwood pottery and Pewabic Tile. The giant columns in the room are formed from Travertine marble imported from Italy. At the base of each of these columns is a block of black marble imported from Belgium. No more of this black marble remains in the quarries from which it was mined.

And that's not the only rare marble in the lobby. Numidian marble was chosen for its unusual blood-red color. No mines in the world quarried it at the time, so Rowland went to Africa, where a mine that had been closed for 30 years was reopened just long enough for Rowland to pick out the marble he needed for the lobby.

And for a ceiling of such height, the main banking lobby is unusually quiet. That's because the ceiling is entirely acoustical, absorbing sound. A 3/4-inch mat of horsehair covered the cement-plaster ceiling. A perforated canvas was placed over that layer and painted.

Anthony Eugenio stenciled and cut the entire ceiling himself. A crew of 10 painters took on the job, using a pallet of 16 colors. Solid gold leaf adorns the sunburst arches; the rays of the sunbursts spread from the center of the ceiling down along the columns.

There also are several large simulated skylights in the center of the ceiling, giving the effect of natural lighting. They are composed of 4-inch square, glass tiles connected with lead channels and a center made of prisms and crinkled glass. All the glass was imported from France.

The wall between the elevators contains a large mosaic of a pine tree and text outlining the bank's purpose. From there. The building's elevator lobbies feature stained glass figures representing Fidelity.

The ceiling, color and stained glass give the Guardian a church-like feel and helped give it its nickname, the Cathedral of Finance.

The banking hall had the same ceiling height, but featured a hand-painted canvas ceiling, which was stretched over horsehair to dampen sound. Upon entering the hall, to the left and right were Art Deco styled teller windows, which flanked a mural of Michigan and its industries, painted by Ezra Winter. Separating the lobby and banking hall was a large screen of Monel metal with Art Deco styling, complete with a Tiffany glass clock in the center, of which only four clocks of the same style exist.

By the time the building was completed, Union Trust had bought up several other banks and become the Guardian Detroit Union Group, which held 40% of Detroit's banking resources. But the Great Depression hit Detroit -- and the bank -- hard. In 1932, the bank went into receivership as the New Union Building Corp.

During World War II, the building was used as a command center for the Army as it coordinated ordinance production. The New Union Building Co. took the building back over after the war, but the bank filed for bankruptcy in 1949. It was sold at auction in 1952 to the Guardian Building Co. of the Michigan Bank Corp.

Up until the 1950s, MichCon remained the Guardian's biggest tenant until the gas giant built its own skyscraper - now known as One Woodward - on the site of the Hotel Norton. But MichCon wasn't giving up on the Guardian, actually buying the landmark in 1975, then selling it to General Electric Pension Trust under a leaseback contract. But in January 1983, MichCon separated from American Natural Resources and began listing its corporate address as the Guardian Building. MichCon would later vacate the building after merging with DTE Energy in May 2001.

In 1998, Smith, Hinchman & Grylls - now known simply as the SmithGroup - said it would move into the Guardian, the gem that one of its architects had designed 70 years earlier.

The Sterling Group bought the Guardian in the fall of 2003 and plunked down more than $14 million in improvements into it. But the biggest change was the announcement that Sterling would open the building up to the public, the first time in more than a quarter century that non-employees were allowed to enter the masterpiece.

In July 2007, Wayne County announced that it was going to buy the Guardian Building for $14.5 million and relocate some of its offices to the landmark. Unfortunately, the county would be vacating its offices in an even older Detroit landmark, the Old Wayne County Building.

The Guardian was designated a National Historic Landmark in June 1989.