A new study by Italy's Monza and Brianza Chamber of Commerce values the Eiffel Tower at about $544 billion, placing it far ahead of other historic locations, including Rome's Coliseum (about $90 billion), Milan's duomo (about $81 billion), the Tower of London (about $70 billion), Madrid's Prado Museum (about $58 billion) and even Great Britain's Stonehenge (about $10 billion).

Outside Europe, the White House in Washington is ranked as one of the world's most valuable landmarks, valued at over $101 billion. But that's still less than 20 percent of the estimated value of the Eiffel Tower.

Because none of these landmarks is actually up for sale, the values were calculated by estimating the inherent worth of the landmark to its home country, including the number of annual visitors and monetary value it brought in through tourism.

The 1,063-foot-tall Eiffel Tower wasn't always seen as so valuable. It was a controversial project at the time of its creation in 1889 and was even designed so that it could be easily demolished. Over 7 million people in 2011 paid to travel to one of its three viewing platforms.

In November 2011, it was announced that the Eiffel Tower would be covered in plants starting in January 2013, temporarily transforming the structure into the world's tallest tree, as part of an effort to highlight sustainable energy efforts.