Cheese fondue became popular in the U.S after Switzerland decided to promote it during the 1964 World's Fair in New York City. The idea of cooking cheese with wine developed in Switzerland in the 17th and 18th centuries. The country began to promote it as a "national" dish just before World War II as a way to get people to eat more cheese. Though the fondue fad has faded somewhat in the United States, the dish is still popular in Switzerland, France and the Italian Alps.
The bubbling cheese is constantly warmed during eating (traditionally with a candle or spirit lamp), so this dish does bring the warmth even though the items that you dip into the communal bowl aren't usually heated. Bread is the most common dipping ingredient, though other items, such as vegetables and meat, may occasionally be used.