As of 2017, what is the only US city to bid for and then turn down hosting the Olympic Games?

The 1976 Winter Olympics, officially known as the XII Olympic Winter Games were held in Innsbruck, Austria for the second time after Denver, CO turned down the honor. Denver was chosen on May 12, 1970 to host the 1976 Olympics. They, along with Sion, Switzerland; Tampere, Finland; and Vancouver, Canada, made bids for the Games. After Denver was chosen, the voters rejected the idea by a margin of 3-2 because of concerns of the environmental impact and a 300% rise in costs. Next, Whistler, British Columbia, Canada, was offered the privilege but they too declined owing to a change of government following elections. Next, the Olympic Committee offered the host to Salt Lake City but citing a lack of financial support, they too rejected the honor. Finally, Innsbruck agreed to host the Winter Olympics.

With the exception of Denver, all the other cities who rejected the 1976 Olympics have gone on to host the games in later years. Denver has never hosted any of the games.