General Motors has (almost) left their building, but gone are the letters that formed the sign that identified the automaker's headquarters for more than 40 years.

On Sunday, April 16, MBM Fabricators and Local 25 iron workers, with an assist by a helicopter, took two hours to carry away 26 letters from their iron-frame perches atop the east and west frontages of the old GM Building.

The landmark 18-foot-tall by 15-foot-wide letters spelling "GENERAL MOTORS" and the red neon tubes that lit them were placed in storage, awaiting a decision by GM about what to do with them. There's speculation that the metal letters may end up at the Henry Ford Museum in Dearborn, at another GM facility or possibly at the Smithsonian Institute.

The signs weren't original to the GM Building, which was built in 1921. One set was added in 1956, the other in 1960.

The removal of the signs came two weeks after the State of Michigan signed a 20-year lease to become tenants in the building. Several state agencies and 4,000 workers will be combined in the building, which has 1.3 million square-feet and was at one time the second-largest building on the planet in terms of space. The building trades will substantially renovate the building.

General Motors is leaving the building in the New Center area for the Renaissance Center, which it purchased in 1996 for $73 million and is spending more than $500 million to renovate. The last of GM's employees should be out of the automaker's old headquarters by October.

MBM Fabricators and Erectors Director of Business Development Eve Mackin said GM hired MBB because of their "close working relationship and similar views on the importance of safety and expertise." She said a safety site plan was developed, the latest in fall protection technology was used, and "both General Motors and MBM Fabricators and Erectors are pleased with the outcome."

MBM acted as general contractor on the project, with Metro Signs (bulb removal), Hall Engineering (electrical), and TF Beck (roof patching) acting as subcontractors.

The letters that spelled out the name of General Motors, on the building the automaker has used as headquarters since 1921, have been moved into retirement.