One World Trade Center, the so-called Freedom Tower currently under construction in Lower Manhattan, technically became New York City's tallest building on Monday, as workers erected steel columns on the 100th floor, 1,271 feet above the street, to make it stand 21 feet higher than the Empire State Building's observation deck.

The Freedom Tower, which is being built to replace the twin towers that fell during the 9/11 terror attacks, won't be completed until 2014. When it is, it will be 104 stories and likely declared the tallest building in America—surpassing Chicago's 1,451-foot Willis Tower at 1,776 feet.

The achievement isn't without a little controversy. As the Associated Press points out, "those bragging rights will carry an asterisk." The reason? A "408-foot-tall needle that will sit on the tower's roof. Count it, and the World Trade Center is back on top. Otherwise, it will have to settle for No. 2."

The world's (undisputed) tallest building is Burj Khalifa in Dubai, which stands at 2,717 feet.

Controversy aside, New York Mayor Mike Bloomberg marked Monday's milestone in a statement:

The New York City skyline is—once again—stretching to new heights. The latest progress at the World Trade Center is a testament to New Yorkers' strength and resolve—and to our belief in a city that is always reaching upward. This building has been a labor of love for many, and I congratulate the men and women who have worked together to solve the challenges presented by this incredibly complex project. Today our city has a new tallest building—and a new sense of how bright our future is.

The operators of the Empire State Building released a statement welcoming 1 WTC's progress, too:

The world's most famous office building, the ancestor of all super-tall towers, welcomes our newer, taller cousin to the skyline. We've watched you grow, and now we salute you.

(Source: http://news.yahoo.com/blogs/lookout/one-world-trade-center-freedom-tower-becomes-york-182905853.html)