However, the Sun-Times notes the building's 2.4-million-sf size equates to the Aon Center at 200 E. Randolph St., which stands 80 stories. Nonetheless, that would dwarf all other buildings in the River North area, as well as many across the river in the Loop.

"I think it would be inappropriate to build the world's tallest building on that site," says Grubb & Ellis senior vice president and director Christopher R. Hill. Before joining Grubb & Ellis in January, he was Mayor Richard M. Daley's planning and development commissioner.

However, Daley himself appears enthusiastic about a plan that could allow the city to regain its title of being home to the world's largest building, reportedly stressing architectural quality in talks with Trump and Hollinger officials.