“The location is outstanding as far as the potential for multiple-family residential,” he said. “It would be a major project to accomplish that.”

An institution would be the most likely buyer, experts said. Offices line the perimeter of some floors. Meeting rooms — large and larger — occupy much of the building’s interior. A new owner would have a free hand with some of the space because the Masons never completed the building.

For example, the fourth floor and mezzanine remain bare concrete, said John Vollmann, the building’s manager. A 1,000-seat dining room planned for the basement was never constructed. Four of the six elevator shafts are empty. And an auditorium built to hold 2,200 people is seatless and bare.

Vollmann said the Masons tried to raise more money after opening the building for $4.4 million in 1926, but the Depression struck three years later and fundraising languished. Even uncompleted, the building has many opulent flourishes.

Some meeting rooms have pilasters and elaborate, coved ceilings. The lobby and mezzanine are a riot of marble. Two big rooms occupy the structure’s top level, designed to resemble a Greek temple. One room is 100 feet by 75 feet with a 48-foot ceiling, Vollmann said. Stained glass panels line the room.