LA is now home to the tallest building west of the Mississippi

Critics might argue that a spire rising nearly 200 feet above the top of the building should not count, but it meets the criteria of the Council on Tall Buildings and Urban Habitat, which lists the world's tallest buildings based on the "architectural top of the building." A 2-foot lightning rod at the very top, however, doesn't count.

The skyscraper is still dwarfed by buildings on the East Coast and overseas. In the United States, One World Trade Center is 1,776 feet tall, making it the sixth-largest completed building in the world. The tallest building, the Burj Khalifa in Dubai, rises 2,717 feet, or more than a half-mile high.

The L.A. building's spine and sail have programmable LEDs that can provide colorful illumination and visuals.

The tower includes an 889-room InterContinental hotel, a shopping mall and an observation deck.