At the ground, tower design is equally critical.

The tower design had a series of faceted surfaces that would help light and air travel throughout the building.

Although the tower design changed, the suit said, it ultimately "retained the spirit and key elements of Libeskind's vision."

The Mod-0 was also used to test the first steel shell towers, now the dominant tower design.

The tower design is almost unique in the Tibetan world.

Pelli said the tower design resembled a rosebud about to bloom.

The compliant tower design is more flexible than conventional land structures to cope better with sea forces.

The tower design includes an observation deck, restaurant, ballroom and parking garage with 600 spaces.

In each case, a tower design will significantly alter the skyline of one of the world's most beloved cities.

Visitors were invited to vote and overwhelmingly chose the single tower design.