Read the excerpt and answer the question that follows.

While the Sears Tower is arguably the greatest achievement in skyscraper engineering so far, it’s unlikely that architects and engineers have abandoned the quest for the world’s tallest building. The question is: Just how high can buildings be built? Structural engineer William LeMessurier has designed a skyscraper nearly one-half mile high, twice as tall as the Sears Tower. Architect Robert Sobel claims that existing technology could produce a 500-story building.

From Ron Bachman, "Reaching for the Sky." Dial (May 1990): 15.

What is the topic of this passage?

The quest to create the world’s tallest building
The history of the Sears Tower
Struggles in contemporary engineering
Challenges faced by architects