Denver International Airport (IATA: DEN, ICAO: KDEN), commonly known as DIA, serves as the primary airport for a large region surrounding Denver. DIA is 18.6 miles (30 km) east-northeast of the Colorado State Capitol. DIA is the eighteenth busiest airport in the world and ranks sixth in the United States, with 58,266,515 passengers passing through it in 2016. It covers more than 53 square miles (137.3 km2), making it the largest airport by land area in the United States and larger than the island of Manhattan. Denver serves as a major hub for United Airlines, is the headquarters for Frontier Airlines, and is the fastest-growing focus city for Southwest Airlines.
The Colorado Territory was created on February 28, 1861, Arapahoe County was formed on November 1, 1861, and Denver City was incorporated on November 7, 1861. Denver City served as the Arapahoe County Seat from 1861 until consolidation in 1902. In 1867, Denver City became the territorial capital. With its newfound importance, Denver City shortened its name to Denver. On August 1, 1876, Colorado was admitted to the Union.
Denver has many nationally recognized museums, including a new wing for the Denver Art Museum by world-renowned architect Daniel Libeskind, the second largest Performing Arts Center in the nation after Lincoln Center in New York City and bustling neighborhoods such as LoDo, filled with art galleries, restaurants, bars and clubs. That is part of the reason why Denver was, in 2006, recognized for the third year in a row as the best city for singles. Denver's neighborhoods also continue their influx of diverse people and businesses while the city's cultural institutions grow and prosper. The city acquired the estate of abstract expressionist painter Clyfford Still in 2004 and built a museum to exhibit his works near the Denver Art Museum. The Denver Museum of Nature and Science holds an aquamarine specimen valued at over $1 million, as well as specimens of the state mineral, rhodochrosite. Every September the Denver Mart, at 451 E. 58th Avenue, hosts a gem and mineral show. The state history museum, History Colorado Center, opened in April 2012. It features hands-on and interactive exhibits, artifacts and programs about Colorado history. It was named in 2013 by True West Magazine as one of the top-ten "must see" history museums in the country. History Colorado's Byers-Evans House Museum and the Molly Brown House are nearby.