Itineraries - World's most popular landmarks When completed in A.D. 82, the Colosseum could hold 50,000 Romans to watch gladiators battle to the death. By Sarah Spagnolo, Travel+Leisure There's a site along the far west side of Manhattan that lures millions to its meandering walkways and scenic lookouts: the High Line, a converted rail bed that's now an elevated park. Though less than three years old, the High Line has already become one of the world's most popular landmarks. Slideshow: See the the top 25 most popular landmarks That's the verdict according to T+L's first-ever landmarks survey, in which we asked readers to rank contenders in six categories - and flag the ones they've actually traveled to see. We used the latter results to determine the world's most popular landmarks, a revealing list of longtime favorites and buzzed-about newcomers like the High Line. A total of five New York landmarks made it into the top 25 most popular list, including the city's newest public space: the National September 11 Memorial. Remarkably, more than half of those who voted for the memorial in our survey have visited the reflecting pools, which opened only in Fall 2011. "Hundreds of thousands of visitors from all 50 states and more than 120 countries have come to the National September 11 Memorial," affirms its president, Joe Daniels. The responses from these visitors continue to be overwhelmingly positive. Landmarks that have played a significant role in history and that are instantly recognizable symbols naturally pique our travel interest. At No. 5, London's Big Ben, a clock tower and 13-ton bell, has attracted onlookers since it started counting the minutes in 1859. Rome's Colosseum is the city's most popular landmark and has given travelers a new reason to visit; below-ground tunnels, where gladiators once prepared for combat, opened to the public in 2010 for the first time in modern history. Perhaps this development helped the Colosseum, No. 6, beat out the best-known structure of the classical world, Greece's Acropolis, which came in at No. So which landmark is so popular that it's been visited by the highest number of T+L readers? None other than Lady Liberty. For the best views of the Statue of Liberty illuminating the Hudson River at twilight, head back to the High Line, which has a straight-on view from the woodsy area next to the 10th Avenue Square.