The Jefferson National Expansion Memorial is a national park located in St. Louis, Missouri. It was established to honor the westward expansion of the United States and features the iconic Gateway Arch, which stands 630 feet tall. The memorial also includes the Museum of Westward Expansion, showcasing artifacts and exhibits related to the history of the American frontier. The memorial was dedicated in 1965 and is named after Thomas Jefferson, the third President of the United States, who played a significant role in the country's expansion. The site attracts millions of visitors each year, offering stunning views of the Mississippi River and the city skyline.