A new study suggests many Americans have not visited the most popular places of interest around the country or even in their hometown. The study found that 25 percent of Americans have yet to visit iconic landmarks in their own cities. Twenty-three percent said they had not visited any of the nation's natural wonders, famous buildings or historic battlefields. The study was a project of the research service OnePoll and Zipcar, a car-sharing company. Researchers questioned 2,000 Americans. Only 33 percent of them said they had been to Niagara Falls and just 28 percent had been to Arizona’s Grand Canyon. The study showed that only 30 percent had been to New York’s Empire State Building. Only 22 percent had ever visited the National Mall in Washington, D.C. Many Americans say they would like to travel more.