1941 was a year of tragic events. Adolf Hitler began the first phase of mass killings by gas chamber in Nazi Germany, and on Dec. 7, the Japanese launched a surprise attack on the U.S. fleet at Pearl Harbor in Hawaii, prompting America to enter World War II.

Despite darkening clouds overseas, American culture shined. Orson Welles’ film "Citizen Kane" premiered, and Disney’s fourth animated feature, "Dumbo," was released. Drive-in fast-food restaurants and drive-in movies grew in popularity. And General Mills introduces the popular breakfast cereal CheeriOats, known today as Cheerios.

In the advertising world, the first commercial legally shown on American television was aired prior to a baseball game between the Brooklyn Dodgers and Philadelphia Phillies, launching commercialized television. In print, advertising focused even more intensely on patriotism and American support, using robust war imagery and pro-American messages.

This article contains a selection of advertisements that appeared in HPAC Engineering magazine, then called Heating, Piping and Air Conditioning, in 1941.