St. Louis, Missouri earned the nickname "Gateway to the West" back in the 1800's for the crucial role it played in the westward expansion of the United States. Today, the west is pretty well settled, but the city's most prominent landmark stands as an enduring reminder of the ways it shaped the country. At 630 feet, the Gateway Arch is the tallest national monument in the United States, towering over the Jefferson National Expansion Memorial and giving St. Louis an unmistakable skyline. Opened to the public in 1965, the arch was designed by Finnish-American architect Eero Saarinen and is truly a wonder of modern engineering. The cross sections of its legs are formed by equilateral triangles made of concrete and steel, and are covered with shiny stainless steel that reflects the sun even on cloudy days. The interior of the arch is hollow, allowing a cutting-edge elevator system with gimbaled cars that resemble ferris wheel gondolas to ferry visitors to an observation deck at the top. Once at the arched observation area, the view is nothing short of breathtaking, with a scenic panorama of the Mississippi River, southern Illinois, and the city of St. Louis spread out before you. You'll understand why so many 19th century settlers decided to make a home right here. Starwood has six St. Louis hotels, including the luxurious Westin St. Louis.

[image via BVH]