Similar to a City-State, Denver is a City-County. Denver's entire county is a city and the governing powers of the city and county are one. Denver is also the capitol of the State of Colorado. The City-County government and the State of Colorado government all operate out of Capital Hill district of downtown Denver. These governing institutions form a mall, much in the way they do in Washington DC. In the heart of this mall is Civic Center Park. The state capital building and the Denver City-County building sit on each side of Civic Center Park and face each other. Here is the view of each from this central vantage point; courtesy of Stepper77:
Colorado State Capital Building
Denver City-County Building